Skip to main content
NCBI home page
Food Chemistry: Molecular Sciences logoLink to Food Chemistry: Molecular Sciences
. 2025 Sep 6;11:100297. doi: 10.1016/j.fochms.2025.100297

Regulatory role of calcium sulfide in ripening delay of postharvest bananas

Hong Xu a,b, Xueting Bi a,b, Junjie Xing a,b, Mengqian Guo b, Haoran Zhang a, Xuejie Zhang a, Wei Li a,⁎, Bingfu Lei a,b,⁎
PMCID: PMC12466287  PMID: 41019382

Abstract

Hydrogen sulfide (H₂S) has been demonstrated to delay ripening and senescence in various fruits, offering great capability for postharvest preservation. However, existing application methods face several limitations, such as unstable release, difficulty in dosage control, and safety concerns, and its regulatory mechanisms in fruit systems remain unclear. In this study, calcium sulfide (CaS) was used as a slow-release H₂S donor that gradually releases H₂S through reactions with airborne moisture and carbon dioxide to treat bananas. CaS treatment significantly downregulated key ethylene biosynthetic genes and corresponding enzymes (ACO and ACS), thereby reducing ethylene production. The expression of starch-degrading and cell wall-modifying genes was also suppressed, delaying starch breakdown and cell wall disassembly. Enzyme assays and transcriptomic analyses confirmed that CaS delays banana ripening through coordinated regulation at both transcriptional and biochemical levels. As a result, CaS treatment effectively extended shelf life and maintained fruit quality of bananas. These findings reveal the potential of CaS as a novel H₂S-releasing agent for postharvest preservation.

Keywords: Banana fruit, Ripening, Calcium sulfide, Ethylene production, Starch degradation, Cell wall breakdown

Graphical abstract

Unlabelled Image

Open in a new tab

Highlights

  • •

    CaS powder as a slow-release H2S donor successfully prolonged the shelf life of bananas to 14 days without reducing final quality development.

  • •

    CaS treatment induces postharvest ripening of bananas by affecting multiple metabolism pathways (ethylene, starch and cell wall).

  • •

    The regulatory mechanism of CaS in banana ripening from gene level to metabolic substances and fruit phenotype level was illustrated.

1. Introduction

Banana (Musa spp.), as one of the most traded fruits worldwide, is a vital economic crop in tropical and subtropical regions (Al-Dairi et al., 2023). According to the latest statistics released by the Food and Agriculture Organization of the United Nations (FAO) in October 2023, the global production of bananas reached 139 million tons in 2023. However, due to inadequate postharvest storage and transportation methods, approximately 18 % to 22 % of the total yield equivalent to 22.3 to 27.3 million tons w lost annually along the supply chain due to spoilage or quality deterioration, resulting in direct economic losses of USD 6.2 to 7.5 billion (Al-Dairi et al., 2023). As a typical climacteric fruit, bananas are highly susceptible to rapid ripening after harvest due to ethylene release. The ethylene-induced physiological responses, coupled with reactive oxygen species (ROS) accumulation and structural damage at the cellular level, lead to peel browning, pulp softening, and nutrient degradation (Liu, 2023). Therefore, the development of efficient, safe, and cost-effective preservation technologies is of great significance for reducing postharvest losses, extending shelf life, and enhancing the overall value of the banana industry (Cefola & Pace, 2023).

Currently, postharvest preservation technologies for bananas can be broadly categorized into three main approaches: physical regulation, chemical treatment, and biological preservation (Al-Dairi et al., 2023). Physical methods, such as low-temperature storage (13–15 °C) and modified atmosphere packaging (MAP), can effectively delay ripening (Satekge & Magwaza, 2022). However, these approaches involve substantial capital investment—for example, the construction cost of a controlled atmosphere storage facility is approximately USD 1000 per cubic meter, and still may induce chilling injury (Bramlage, 1982), leading to peel browning (Karthiayani et al., 2006). Chemical treatments primarily involve the application of various synthetic preservatives. Among them, 1-methylcyclopropene (1-MCP) is the most widely used, functioning by inhibiting the binding of ethylene to its receptors in fruit tissues, thereby delaying ripening (Rahman et al., 2024). Nevertheless, its efficacy is highly dependent on precise concentration control (typically 0.5–1.0 μL), and excessive application can result in incomplete or abnormal ripening (Satekge & Magwaza, 2022). Sodium hypochlorite (NaClO) and sulfur dioxide (SO2) exhibit excellent antimicrobial efficacy, but their use raises concerns about chemical residues(Gil et al., 2019; Xiao et al., 2019). Biological preservation techniques, such as chitosan-based edible coatings and plant hormone treatment, are considered environmentally friendly and safe (Adiletta et al., 2021). However, their application is limited by narrow antimicrobial spectra and relatively high costs (approximately USD 5–8/kg), which hinder large-scale commercialization (Elsabagh et al., 2023). Therefore, it is urgent to develop novel preservation technologies that simultaneously offer high efficacy, safety, and cost-effectiveness.

Material applications on plants have been showing significant effects (Li et al., 2022; Li, Lin, et al., 2024; Li, Wang, et al., 2024). In recent years, hydrogen sulfide (H₂S), a gaseous signaling molecule, has emerged as a research hotspot in postharvest preservation due to its multifaceted roles in redox homeostasis regulation, ethylene biosynthesis inhibition, and delaying fruit senescence (Cefola & Pace, 2023). For instance, fumigation with 0.8 mM NaHS (a common H₂S donor) has been shown to extend the shelf life of bananas by 3–5 days (Liu, 2023). However, conventional liquid donors such as NaHS suffer from limitations including narrow effective concentration range, operational complexity, poor storage stability, and dependence on specialized equipment. In contrast, calcium sulfide (CaS) powder has been proposed as a solid-state H₂S donor that releases H₂S in a sustained manner, enhancing preservation efficacy (Deng et al., 2025). Under ambient temperature and humidity, CaS can continuously release hydrogen sulfide (H₂S) through spontaneous reactions with water vapor and carbon dioxide in the air. The release process is governed by both diffusion limitations and the formation of surface product layers on CaS powder. This sustained-release behavior provides a favorable gaseous microenvironment for postharvest preservation of fruits and vegetables, effectively delaying ripening and senescence. Compared with traditional H₂S fumigation methods, solid CaS powder offers improved safety, greater stability(Hu et al., 2021，Zhu et al., 2020), and environmentally benign reaction byproducts (e.g., CaCO₃ and CaSO₄), demonstrating superior environmental compatibility (Deng et al., 2025).

In this study, CaS powder is used as a slow-releasing hydrogen sulfide (H₂S) donor. By reacting with moisture and carbon dioxide in the air, CaS gradually released H₂S, which was used to treat postharvest banana fruits. The H₂S release behavior of CaS over 48 h was characterized. As illustrated in the graphic abstract, CaS treatment delayed banana fruit ripening through a multi-level regulatory mechanism: on one hand, it suppressed the expression of key ethylene biosynthesis enzymes, ACC synthase (ACS) and ACC oxidase (ACO), along with their associated genes (e.g., MαACSs and MαACOs), thereby inhibiting ethylene production and release; on the other hand, it downregulated the transcription of starch degradation-related genes, delaying starch hydrolysis. In parallel, the expression of pectinase and cellulase genes was reduced, resulting in decreased enzymatic activity and subsequently slowing down cell wall degradation. Moreover, appropriately shortening the CaS treatment duration (from 10 days to 4 days) allowed normal ripening while significantly prolonging shelf life and enhancing the soluble sugar content in the pulp, effectively maintaining overall fruit quality.

2. Materials and methods

2.1. Chemical reagents

CaS powder was purchased from Macklin biochemical technology Co., Ltd. (Shanghai, China). Ethephon was purchased from Huayi chemicals Co., Ltd. (Shanghai, China). Sporgon was purchased from Keagio biotechnology Co., Ltd. (Shandong, China). I2 and KI was purchased from Macklin biochemical technology Co., Ltd. (Shanghai, China).

2.2. Fruit and handling

Banana fruits (Musa acuminata AAA group, Cavendish subgroup) at mature green stage were obtained at a local fruit wholesale market in Guangzhou, China. The banana fruits were divided into single fingers, then the fruit with uniform size and free from physical wounds or visible diseases were immersed in 500 mg/L Sporgon for 1 min to disinfect field diseases, and naturally dried in the open air for 1 h. Subsequently, banana fruits were treated with ethylene for 18 h to induce ripening. Then a total of 375 bananas fruits were randomly separated into 5 treatment groups, with each group containing 75 fruits (three replicates of 25 fruits each). The fruits were placed in 16 L sealed boxes together with 0, 0.5, 1.0, 1.5, 2.0 g of CaS powder (contained in a non-woven bag), respectively. The banana fruits were stored in 20 °C with relative humidity of 90 % - 95 % for 10 days, The CaS powder bag was replaced every 48 h. During the storage, banana fruits of each group were chosen for physiological index measurement and sampling. Each treatment involved three biological replicates.

2.3. Ripening index determination

Firmness, peel color and ethylene production were used to estimate the ripening process of banana. Firmness of banana peel and pulp was assessed by means of a penetrometer (Instron, MA, USA, model No. 5542) set with a cylindrical 6-mm diameter flat-faced plunger, and the results were presented as Newton (N). Ethylene release was estimated by putting five fruits from each group in an airtight plastic box covered by a rubber stopper for 2 h at 20 °C. Gas sample of 1 mL was collected and analyzed for ethylene by gas chromatography (Shimadzu, Kyoto, Japan, model No. GC-17 A) following previous method (Wang et al., 2006).

2.4. Measurement of airborne H2S concentration and endogenous H2S content

H2S concentration from 0 h to 48 h was detected using KP816 handheld gas detector from Zhongan gas detection company (Henan, China) with an electric air pump. The content levels of endogenous H2S were determined using commercial kits from Cominbio (Suzhou, China, Cat. No. H2S-2-G) according to the manufacturer's procedures.

2.5. Characterization of CaS powder

CaS powder samples (0.1 g) were scanned with an X-ray diffractometer (Rigaku, Tokyo, Japan, Ultima IV) according to the method (Chen et al., 2021). The test conditions were set as follows: X-ray source was set at CuK α, and samples were measured with scattering angles from 10 to 80°(2θ) and scanning rate of 4°min−1. The data was computed using the MDI-Jade 5.0 software.

The structure of CaS powder was observed in a scanning electron microscope (Zeiss, Oberkochen, Germany, EVO MA 15). 0.1 g of CaS powder was fixed on a metal table with conductive tapes and coated with gold powder. Images were then taken at 5000-times enlargement.

2.6. Starch granule isolation

Banana fruit at 0, 4 and 8 d ripening stages were used to extract starch granules. A previous method was used (Santelia & Zeeman, 2011). In brief, approximately 20 g of banana pulp was ground in a grinder and incubated in 0.05 L of starch granule extraction solution. Then the the samples were sieved through a 200-mesh sieve. Starch samples were harvested, dried, and then preserved for further use.

2.7. Morphological structure of starch granules and cell wall

The morphology of banana starch granules cell wall structure from banana fruits of each treatment group was compared by observation in a scanning electron microscope (Zeiss, Oberkochen, Germany, EVO MA 15). 0.1 g of each starch sample was fixed on a metal table with conductive tapes, the cell wall sample was obtained through biotic sample preparation and fixed on a metal table with conductive tapes. Samples were coated with gold powder. Images were then taken at 2000- and 5000-times enlargement.

2.8. I2-KI solution staining

The method was adopted from the previous study (Liu et al., 2021). Banana fruit of each ripening stage were cut vertically into two halves and horizontally into 5 mm thick slices. The cut fruit parts were immersed in 0.1 % I2-KI solution for 120 s. The effect of staining was evaluated by estimating the area and intensity of staining.

2.9. RNA isolation and gene expression assays

Total RNA from banana pulp was isolated with refer to the hot borate method (Wan & Wilkins, 1994). cDNA was prepared using HiScript® II Q Select RT SuperMix for qPCR with gDNA wiper (Vazyme, Nanjing, China). RT-qPCR was undertaken on a CFX96 detection equipment (Bio-Rad, CA, USA) using ChamQ SYBR qPCR Master Mix (Vazyme, Nanjing, China). Expression level of candidate gene was computed using the method of cycle threshold (Ct) 2-△△Ct. Banana MaRPS4 was adopted as an internal reference (Chen et al., 2011). All primers in this study are enumerated in Table S1.

2.10. Determination of starch and total soluble sugar contents

Procedures for the evaluation of total starch were as described previously (Hansen & Møller, 1975). The total soluble sugars were estimated according to a previously reported method (Deng et al., 2021).

2.11. Determination of α-amylase, β-amylase, and isoamylase activities

The activities of α-amylase, β-amylase, and isoamylase were estimated using the commercial kits from Cominbio (Suzhou, China, Cat. No. DFMA-2-Y, DFMB-2-Y, and DBE-2-Y) according to the manufacturer's procedures.

2.12. Determination of pectin and Cellulose contents

The activities of pectin and Cellulose contents were estimated using the commercial kits from Cominbio (Suzhou, China, Cat. No. ZGJ-2-G and CLL-2-Y) according to the manufacturer's procedures.

2.13. Determination of Cellulase and pectinase activities

The activities of Cellulase and pectinase activities were estimated using the commercial kits from Cominbio (Suzhou, China, Cat. No. PE-1-G and CL-2-Y) according to the manufacturer's procedures.

2.14. Statistical analysis

The raw data collected was calculated and sorted using Excel, and statistical analysis was performed using SPSS version 27.0.1. Origin was used for graphs. All data presented in the text are mean and SD calculated from 3 biological replicates. One-way analysis of variance (ANOVA) or Student's t-test was used to analyze statistically significant difference among samples (*P < 0.05 or **P < 0.01).

3. Results and discussion

3.1. Characterization of CaS powder transformation and H2S releasing

As shown in Fig. 1A, XRD analysis reveals the stepwise transformation mechanism of CaS during storage with banana fruit. At the initial stage (0 h), the diffraction pattern is dominated by characteristic peaks of CaS, accompanied by minor signals corresponding to Ca(OH)₂, CaCO₃, and CaSO₄. After 24 h, the intensity of CaS peaks markedly decreases, while Ca(OH)₂ and CaCO₃ peaks increase, indicating hydrolysis of CaS and subsequent reaction of Ca(OH)₂ with atmospheric CO₂ to form CaCO₃. Concurrently, partial oxidation of sulfur species leads to the formation of CaSO₄. By 48 h, CaS is nearly depleted, with CaCO₃ emerging as the dominant crystalline phase, accompanied by residual CaSO₄ and Ca(OH)₂, reflecting the complete transformation of CaS into stable products (Yu et al., 2023). Fig. 1B further corroborates this transformation process through the time-dependent evolution of H₂S concentration. During the initial 0–8 h, the H₂S level remains low, followed by a rapid increase, peaking at approximately 16–20 h (∼45–50 ppm). Subsequently, the concentration gradually declines, reaching ∼30 ppm at 48 h. This trend is characteristic of a diffusion-controlled slow-release profile (Foster et al., 2019). The decrease in H₂S concentration can be attributed to two.

Fig. 1.

Fig. 1

Open in a new tab

(A) XRD patterns of CaS powder samples at 0 h, 24 h and 48 h. (B) Airborne H2S concentration in sealed box. (C) Endogenous H2S content levels of banana fruits. Different letters indicate significant differences at p < 0.05 level.

primary factors: (1) the accumulation of solid products such as Ca(OH)₂ and CaCO₃ on the CaS surface forms a diffusion barrier, limiting water penetration and further hydrolysis (Bora et al., 2024); (2) H₂S is partially absorbed or consumed by the banana peel tissue (Yu et al., 2023), as evidenced by the elevated H₂S content in the peel of CaS-treated bananas (Fig. 1C), thereby reducing the net gaseous H₂S concentration. This solid–liquid–gas multiphase reaction process, regulated by diffusion and surface passivation, enables CaS to continuously release H₂S over 48 h, rather than discharging it all at once, achieving a controlled and sustained gas supply. Morphological changes in CaS particles at 0 h, 24 h, and 48 h were further examined by scanning electron microscopy (SEM). As displayed in Fig. S1, initially (0 h), CaS particles exhibited smooth surfaces with well-defined granular structures. Over time, small particulate aggregates began to form on the surface as a result of progressive reactions between CaS and environmental H₂O and CO₂, generating low-solubility inorganic products such as Ca(OH)₂, CaCO₃, and CaSO₄ (Bora et al., 2024). At 24 h, irregular fine particles were observed to increasingly cover the surface. By 48 h, these nanoscale particles had aggregated extensively, forming a dense and continuous surface layer. This coating likely impedes further contact between CaS and moisture, playing a critical role in modulating the H₂S release kinetics.

3.2. Ripening index of banana fruits

Ethylene is a key gaseous phytohormone that plays a central role in promoting banana fruit ripening (Bapat et al., 2010). Bananas treated with ethephon for artificial ripening continue to release substantial amounts of ethylene during postharvest storage (Quoc et al., 2014), thereby accelerating the ripening process. Typical indicators of banana ripening include peel degreening and softening of both the peel and pulp. As ripening progresses, the fruit peel rapidly turns yellow, accompanied by a significant decline in tissue firmness (Sinanoglou et al., 2023). As shown in Fig. 2A, bananas in the ETH group exhibited noticeable yellowing by day 4 and were almost fully yellow by day 8. In contrast, four groups treated with different amounts of CaS powder (0.5 g, 1.0 g, 1.5 g, and 2.0 g) as a solid H₂S donor exhibited significantly delayed peel yellowing. All CaS-treated groups retained a visibly green peel even after 10 days of storage. Fig. 2B illustrates the ethylene release dynamics during storage. Compared to the ETH group, all CaS-treated groups showed markedly reduced ethylene emissions, with peak release occurring earlier. Specifically, the ETH group reached a maximum ethylene release of 7.19 nmol/kg/s on day 6, whereas the 0.5 g and 1.0 g CaS groups peaked earlier on day 4, with values of 6.46 nmol/kg/s and 4.58 nmol/kg/s, respectively. The 1.5 g CaS group exhibited its ethylene peak on day 2, with a significantly lower value of 2.71 nmol/kg/s. Although the 2.0 g CaS group peaked on day 6, it had the lowest ethylene release at only 2.26 nmol/kg/s. These results indicate a clear dose-dependent inhibition of ethylene production, with the 2.0 g CaS group showing the most pronounced reduction in total ethylene release. CaS treatment appears to induce an earlier peak in ethylene release, followed by a substantial decline during later stages. Fig. 4C and D depict the changes in peel and pulp firmness, respectively. In the ETH group, both peel and pulp firmness declined rapidly during storage, reaching 49.48 N and 7.37 N by day 4, and further decreasing to 21.73 N and 6.08 N by day 10. In contrast, all CaS-treated groups exhibited significantly better firmness retention. The 1.5 g CaS treatment group demonstrated the best preservation of tissue firmness, maintaining peel and pulp firmness at 70.15 N and 26.59 N, respectively, on day 10. In summary, CaS treatment effectively suppressed ethylene production, delayed peel yellowing, and maintained higher firmness in both peel and pulp during postharvest storage, highlighting its potential as a promising approach for extending the shelf life of bananas.

Fig. 2.

Fig. 2

Open in a new tab

Physiological changes during ripening. Appearance changes (A), ethylene production (B), peel firmness (C), and pulp firmness (D) of banana fruits treated with 0, 0.5, 1.0, 1.5 and 2.0 g CaS for 10 days. Appearance (E), starch content (F) and soluble sugar content (G) of banana fruits treated by 0 and 1.5 g CaS for 4 days. Different letters indicate significant differences at p < 0.05 level.

Fig. 4.

Fig. 4

Open in a new tab

Photographs of I2-KI staining (A), decreasing starch content (B) and increasing soluble sugar content (C) of banana fruits treated by 0 and 1.5 g CaS for 10 days. Different letters indicate significant differences at p < 0.05 level. Enzymatic activities of α-amylase (D), β-amylase (E), and isoamylase (F) in banana fruits were suppressed by CaS treatment. Relative expression levels of starch degradation related genes (MαPWD1、MαGWD1、MαAMY2B、MαAMY2C、MαAMY3、MαBAM4、MαBAM7、MαISA3、MαSEX4 and MαLSF1) in banana fruits (G) were downregulated by CaS treatment. Different letters indicate significant differences at p < 0.05 level.

To demonstrate that CaS treatment is capable of effectively delaying the ripening of bananas without compromising their final maturity or quality development, a comparative study was conducted between an ETH group and a group treated with 1.5 g of CaS for 4 days. By limiting the duration of CaS exposure, the objective was to delay the onset of ripening rather than maintain the fruit in an unripe state throughout storage. As shown in Fig. 2E, bananas in.

the ETH group began visible degreening by day 4 and reached full yellow coloration by day 7. In contrast, the CaS-treated bananas exhibited noticeable yellowing only after 7 days and achieved full yellow coloration around day 10. Between days 10 and 14, bananas in the ETH group developed numerous dark speckles (indicative of anthracnose) and browning spots (caused by mechanical damage), along with blackening and fungal growth (crown rot) at the fruit stalk. Conversely, bananas in the CaS group showed no apparent signs of disease or damage between days 10 and 12. Only light speckling appeared by day 14, and yellowing at the pedicel was slower than on the peel, suggesting that CaS treatment helped maintain better external quality and delayed senescence symptoms. Changes in starch content during storage are shown in Fig. 2F. In both groups, starch content decreased continuously. The ETH group exhibited a rapid decline from day 0 to day 7, followed by a slower decrease from day 7 to day 14. The CaS group, however, followed a “slow-fast-slow” degradation pattern, with a slight decrease during the initial 0–4 days, a sharp drop from day 4 to day 10, and a gradual decline from day 10 to day 14. During the 4–10 day window, starch content in the CaS group was significantly higher than in the ETH group. By day 14, the final starch contents were comparable (44.11 g/kg in ETH and 46.95 g/kg in CaS), indicating that CaS treatment temporarily delayed starch degradation, but normal ripening metabolism resumed after the treatment period. Total soluble sugar (TSS) content dynamics are shown in Fig. 2G. The ETH group exhibited a rise-then-fall trend, whereas the CaS group showed a continuous increase. In the ETH group, sugar content increased rapidly from day 0 to day 4, then more slowly from day 4 to day 10, peaking at 92.97 g·kg−1, before declining to 81.65 g·kg−1 by day 14. In the CaS group, the sugar content increased gradually from day 0 to day 4, peaked at the fastest rate between days 4 and 7, and then increased at a slower pace, reaching a maximum of 101.31 g·kg−1 at day 14. Soluble sugar levels are co-regulated by starch degradation (which contributes to sugar accumulation) and respiratory metabolism (which consumes sugars) in various of fruits (Su-Mon et al., 2024). In the ETH group, high respiratory activity likely led to continued sugar consumption after starch breakdown had plateaued, resulting in a decrease in sugar content in the late storage period. In contrast, the sustained increase in sugar content in the CaS group suggests that CaS treatment may have suppressed respiratory activity and reduced sugar consumption. Based on the above results, the 4-day treatment with 1.5 g CaS effectively delayed banana ripening while preserving normal post-ripening quality, significantly extending shelf life, suppressing disease development, and enhancing sugar accumulation, demonstrating promising potential for postharvest preservation.

3.3. Expression of Ethylene biosynthesis related genes

Ethylene is a pivotal gaseous phytohormone involved in regulating the postharvest ripening of fruits and vegetables (Tipu & Sherif, 2024). As illustrated in Fig. 3A, ethylene biosynthesis in plants typically proceeds via the conversion of S-adenosyl methionine (SAM) to 1-aminocyclopropane-1-carboxylic acid (ACC), catalyzed by ACC synthase (ACS), followed by the oxidation of ACC to ethylene (ETH) under aerobic conditions, a reaction catalyzed by ACC oxidase (ACO) (Tipu & Sherif, 2024). Among these, ACS and ACO are considered the rate-limiting enzymes in the ethylene biosynthetic pathway (Tipu & Sherif, 2024). In bananas, ethylene production and release are closely associated with the acceleration of starch degradation and cell wall hydrolysis during ripening. The activities of ACS and ACO directly determine the rate of ethylene synthesis and emission, which are tightly regulated by the expression levels of their respective genes, namely MaACSs and MaACOs. To investigate whether CaS treatment modulates ethylene production in postharvest bananas, both ethylene release and the expression of key ethylene biosynthesis-related genes were analyzed. As shown in Fig. 3B–C, quantitative RT-PCR revealed that, compared to the ETH-treated group, bananas subjected to CaS treatment exhibited a marked downregulation in the relative expression of five key genes involved in ethylene biosynthesis: MaACO1, MaACO4, MaACO13, MaACS1, and MaACS12. These findings indicate that CaS treatment significantly suppresses the expression of ethylene biosynthetic genes during postharvest storage, thereby effectively reducing ethylene production and delaying fruit ripening in bananas.

Fig. 3.

Fig. 3

Open in a new tab

The ethylene biosynthesis pathway in bananas (A). Relative gene expression of MαACSs (B) and MαACOs (C) treated by 0 and 1.5 g CaS for 10 days. Different letters indicate significant differences at p < 0.05 level.

3.4. Starch degradation

As shown in Fig. 4A, the cross-sectional and longitudinal images of banana pulp stained with iodine‑potassium iodide (I₂-KI) solution reveal a blue-purple coloration, resulting from the formation of a starch‑iodine complex (Pesek et al., 2022). The extent and intensity of staining serve as qualitative indicators of starch, darker and more extensive staining corresponds to higher starch content. In the ETH-treated group, the stained area progressively decreases and the color intensity diminishes over the ripening period, indicating a continuous reduction in starch content. Notably, the unstained regions initially emerge at the core of the pulp and gradually expand outward, suggesting that starch degradation initiates in the central tissues and subsequently propagates toward the peripheral regions. In contrast, the CaS-treated group exhibits negligible changes in both staining area and intensity from day 0 to day 10, implying that starch degradation is effectively inhibited and that starch content remains relatively stable throughout storage. Quantitative results for total starch content are presented in Fig. 4B. Both treatment groups display a declining trend in starch concentration over the 10-day storage period. However, a significant divergence emerges on day 4, with the ETH group showing a starch content of 118.91 g·kg−1 compared to 143.50 g·kg−1 in the CaS-treated group, an approximate difference of 17 %. By day 10, the ETH group's starch level further decreases.

to 77.19 g·kg−1, whereas the CaS group retains a much higher level of 135.84 g·kg−1, nearly twice that of the ETH group. During banana ripening, starch degradation results in the accumulation of soluble sugars, thereby increasing fruit sweetness (Pesek et al., 2022). As depicted in Fig. 4C, the total soluble sugar content in both groups rises over time, though with markedly different dynamics. From day 2 onwards, a clear divergence is observed: the ETH group records 22.71 g·kg−1, while the CaS group has only 15.96 g·kg−1. Between days 2 and 4, the ETH group experiences a rapid surge in sugar content, culminating in a peak of 101.79 g·kg−1 by day 10. In contrast, the CaS group only reaches 25.46 g·kg−1 at the same time point, demonstrating a significantly slower rate of starch-to-sugar conversion.

To investigate the morphological changes of starch granules during banana ripening, starch was extracted from the pulp on days 0, 4, and 8 of storage under different treatments and subsequently observed using scanning electron microscopy (SEM). As shown in Fig. S2, at day 0, starch granules from both treatment groups exhibited flattened, irregular round or oval shapes with smooth surfaces. However, from day 4 onward, notable differences emerged between the two groups. In the ETH-treated group, starch granules began to display surface deformations on day 4, including heterogeneous pitting and parallel groove-like striations. By day 8, the granules exhibited pronounced morphological alterations, characterized by a reduction in size and extensive surface erosion, with the majority of the surface covered by parallel grooves. In contrast, starch granules from the CaS-treated group maintained their structural integrity throughout the observation period. Both on day 4 and day 8, the granules remained similar in size and morphology to those at day 0, retaining their smooth surfaces and regular shapes without evident degradation features. These findings suggest that during normal ripening, starch degradation in banana pulp proceeds via surface hydrolysis mediated by amylolytic enzymes, leading to progressive erosion of the granules. The CaS treatment markedly inhibited this enzymatic hydrolysis, preserving the morphological integrity of the starch granules throughout the storage period.

3.5. CaS treatment suppressed activity and transcription of starch hydrolytic enzymes during ripening

The degradation of starch in banana pulp is a complex, highly regulated biological process involving the coordinated action of multiple hydrolytic enzymes and associated gene networks (Xiao et al., 2018). Drawing upon the starch degradation model established in Arabidopsis thaliana, a mechanistic framework for banana starch catabolism was proposed earlier (Zeeman et al., 2010). In this model, key initiating enzymes, glucan water dikinase (MaGWD1) and phosphoglucan water dikinase (MaPWD1)—are transcriptionally upregulated in response to ethylene signaling and accumulate on the starch granule surface. These enzymes catalyze the phosphorylation of glucan chains, increasing granule surface hydrophilicity and thereby facilitating subsequent enzymatic access (Ritte et al., 2002). Following this priming phase, a suite of hydrolases, including α-amylases (MaAMY2B, MaAMY2C, MaAMY3) and β-amylases (MaBAM4, MaBAM7), are recruited to the granule surface, where they cleave the α-1,4-glycosidic bonds of the phosphorylated starch, producing maltose and limit dextrins (Kötting et al., 2005). Concurrently, phosphoglucan phosphatases (MaSEX4 and MaLSF1) remove phosphate groups from glucosyl residues (Bernal et al., 2022), enabling the recycling of phosphorylated intermediates and facilitating complete enzymatic breakdown of the starch polymer in conjunction with debranching enzymes such as MaISA3 (Hu et al., 2016). As shown in Fig. 4D–F, the enzymatic activity profiles for α-amylase, β-amylase, and isoamylase in the ETH-treated group exhibited a coordinated induction over time, with activity peaking at different stages: β-amylase activity peaked on day 4, whereas α-amylase and isoamylase peaked at day 6. This temporal regulation reflects the sequential activation of hydrolytic steps required for efficient starch turnover during fruit ripening. By contrast, the CaS-treated group displayed a markedly suppressed enzymatic response. Throughout the 10-day storage period, α-amylase and β-amylase activities remained at basal levels, with no significant elevation observed. Isoamylase activity followed a similar temporal pattern as in the ETH group, rising to a peak at day 6, but the overall activity level was substantially reduced. These data suggest that CaS treatment disrupts the normal enzymatic cascade involved in starch degradation.

Furthermore, RT-qPCR analysis (Fig. 4G) confirmed that CaS treatment significantly downregulated the expression of a broad array of starch degradation-related genes, including MαPWD1、MαGWD1、MαAMY2B、MαAMY2C、MαAMY3、MαBAM4、MαBAM7、MαISA3、MαSEX4 and MαLSF1. The transcriptional suppression of these key genes provides a mechanistic explanation for the observed decline in enzymatic activities and the subsequent inhibition of starch degradation in banana pulp under CaS treatment. These results indicate that CaS exerts a dual inhibitory effect on starch degradation by both attenuating the expression of starch catabolic genes and reducing the enzymatic activity of key amylolytic proteins. This regulatory suppression contributes to the preservation of starch granule integrity and delays the ripening-associated metabolic shift toward soluble sugar accumulation in banana fruit.

3.6. CaS treatment suppressed cell wall breakdown during banana fruit ripening

During the postharvest ripening of banana fruit, cell wall degradation is a key physiological process responsible for fruit softening (Brummell, 2006). Under the regulation of ethylene signaling, structural polysaccharides such as cellulose and pectin undergo enzymatic hydrolysis mediated by a series of cell wall-modifying enzymes (Ge et al., 2017). This leads to the conversion of insoluble protopectin into soluble pectin and the loosening of intercellular adhesion (Gwanpua et al., 2014). Simultaneously, degradation of cellulose microfibrils and disruption of their cross-linking with hemicellulose cause disassembly of the cell wall framework (Shi et al., 2023). Moderate degradation contributes to the development of a desirable soft and juicy texture (Cordenunsi-Lysenko et al., 2019); however, excessive degradation results in tissue collapse, compromising fruit quality and postharvest shelf life (Li et al., 2023). To investigate the effects of CaS treatment on cell wall integrity in comparison to ethylene treatment (ETH), banana peel samples from both groups were collected at 0, 4, and 8 days, followed by conventional biological specimen preparation and observation under a scanning electron microscope (SEM) at 2000× and 5000× magnification. As shown in Fig. 5, at day 0, both groups exhibited compact and intact cell wall structures, with tightly joined cells and smooth, unbroken surfaces. In the ETH group, noticeable loosening of the cell wall was observed by day 4, characterized by intercellular separation and the appearance of visible gaps.

Fig. 5.

Fig. 5

Open in a new tab

Scanning electron microscope (SEM) images of cell wall structure from banana fruits treated by 0 and 1.5 g CaS for 10 days.

By day 8, the cell wall surface became increasingly rough and was covered with a large amount of amorphous flocculent material, indicating pronounced structural degradation. In contrast, the CaS-treated samples maintained relatively intact morphology at both 4 and 8 days, with tight cell-to-cell adhesion and surface appearance similar to the initial state. These findings suggest that the sustained release of H₂S from CaS effectively inhibits cell wall degradation and may contribute to delaying tissue senescence during postharvest storage.

As shown in Fig. 6A, the cellulose content in banana peel exhibited similar values between treatments at 0 and 2 days, with the ETH and CaS groups recording 96.65 g·kg−1 and 96.94 g·kg−1 at day 2, respectively. From day 2 onward, the ETH group showed a marked decline in cellulose content, with a rapid reduction occurring between day 4 and day 10, ultimately dropping to 27.22 g·kg−1. In contrast, the CaS-treated group maintained a relatively stable cellulose level throughout the 10-day storage period, with the content at day 10 reaching 99.19 g·kg−1—statistically comparable to that at day 0 and equivalent to 364.4 % of the ETH group value. The dynamics of pectin content, presented in Fig. 6B, further highlight the differential effects between the two treatments. Both groups showed a general downward trend in pectin levels from day 2 to day 10; however, the ETH group exhibited a significantly faster rate of decline. A distinct divergence was observed as early as day 4, when the ETH and CaS groups recorded 9.93 g·kg−1 and 11.68 g·kg−1, respectively. By day 10, the gap widened substantially, with the CaS group maintaining 9.71 g·kg−1 of pectin—more than twice that of the ETH group (4.48 g·kg−1).

Fig. 6.

Fig. 6

Open in a new tab

Cellulose content (A) and pectin content (B) maintained higher in bananas of CaS treated group. Supressed enzymatic avtivities of cellulase (C) and pectinase (D) in bananas of CaS treated group. Different letters indicate significant differences at p < 0.05 level. Relative gene expression of genes (E) involving in cell wall breakdown (MαXGTs、MαXTHs、MαXETs、MαEXPs、MαPEs、MαPGs、MαPLs and MαPMEs) in bananas were downregulated by CaS treatment. Different letters indicate significant differences at p < 0.05 level.

As shown in Fig. 6C, cellulase activity in banana peels of the ETH group exhibited a continuous increase, reaching a peak of 505.96 μg·h−1·g−1 at day 10. In contrast, the CaS-treated group showed a slower increase, peaking at 477.41 μg·h−1·g−1 on day 6, followed by a gradual decline to 464.51 μg·h−1·g−1 by day 10. Fig. 6D shows that pectinase (PE) activity in the ETH group followed a rise-then-fall pattern, with a sharp increase from day 2 to 4 and a peak value of 640.04 nmol·min−1·g−1 at day 4, then rapidly decreasing. In contrast, PE activity in the CaS group declined gradually throughout the storage period, reaching 456.68 nmol·min−1·g−1 at day 10. These results indicate that CaS treatment effectively suppressed the activities of cellulase and pectinase, thereby slowing the degradation of cellulose and pectin in the peel and contributing to the preservation of peel structural integrity.

3.7. CaS treatment downregulated the expression of cell wall hydrolases

Cell wall degradation is a complex process regulated by the coordinated action of multiple enzymes (Payasi et al., 2009), whose activities are governed by the expression of corresponding genes (Wu et al., 2023). During fruit softening, key enzymes involved in cell wall disassembly include xyloglucan galactosyltransferase (XGT), xyloglucan endotransglucosylase/hydrolase (XET/XTH), expansin (EXP), pectinesterase (PE), polygalacturonase (PG), pectate lyase (PL), and pectin methylesterase (PME) (Shi et al., 2023), all of which are transcriptionally regulated by gene families such as MaXGTs, MaXTHs, MaXETs, MaEXPs, MaPEs, MaPGs, MaPLs, and MaPMEs (Ren et al., 2023). As shown in Fig. 6E, the relative expression levels of 12 cell wall degradation-related genes were analyzed via RT-qPCR. All 12 genes exhibited varying degrees of downregulation in the CaS-treated group compared to the ETH group during banana ripening. Together with the enzymatic activity data in Fig. C—D, these results demonstrate that CaS treatment downregulates the expression of genes encoding key pectinolytic and cellulolytic enzymes, leading to reduced enzyme activity and consequently delaying cell wall degradation in banana peel.

3.8. Transcriptomic analysis of CaS treated banana fruits

Based on the results that CaS treatment delays banana peel cell wall degradation by downregulating key cell wall-modifying enzyme genes, we further investigated whether CaS induces broader transcriptional reprogramming in banana fruit. To this end, transcriptomic analysis was performed on pulp tissue mRNA extracted from untreated fruit (ETH group at day 6 of storage, labeled E-6d) and CaS-treated fruit (1.5 g CaS treatment at day 6, labeled S-6d). This time point was selected because the ETH group fruit had largely de-greened and yellowed, coinciding with the ethylene peak, whereas CaS-treated fruit remained in the green mature stage. Six cDNA libraries (three biological replicates per group) were constructed and subjected to high-throughput sequencing. Principal component analysis (PCA, Fig. 7 A) revealed clear separation between E-6d and S-6d samples, with tight clustering within groups, indicating significant inter-group differences and low intra-group variability. Pearson correlation analysis further confirmed the consistency of the transcriptomic libraries, demonstrating high data quality (Fig. 7B). Volcano plot analysis (Fig. 7C) identified a total of 24,467 differentially expressed genes (DEGs) between E-6d and S-6d, including 14,789 upregulated and 9678 downregulated genes.

Fig. 7.

Fig. 7

Open in a new tab

Transcriptiomics of banana fruits treated with 0 and 1.5 g CaS for 10 days (samples on 6d were taken, with 3 biological repeats for each group). (A) Principal component analysis (PCA) among the 6 transcriptomic samples. PC1 and PC2 stand for the contribution rates of principal components. (B) Correlation analysis among the 6 transcriptomic samples. (C) Volcano plot of the differentially expressed genes (DEGs) in 2 comparative groups. (D) Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Dot color means the value of -log10(q-value), while dot size represents the number of DEGs enriched in the pathway. (E) A heat map showing the expression levels of genes from the selected 29 DEGs, along with a sankey dot pathway enrichment plot of the same DEGs (the abbreviation “E” stands for ETH group, and “S” stands for CaS + ETH group).

In this study, a total of 145 target genes involved in the regulation of banana fruit ripening-encompassing key metabolic pathways such as ethylene biosynthesis, starch degradation, and cell wall hydrolysis—were identified through literature review and transcriptomic data mining. KEGG pathway enrichment analysis (Fig. 7D) revealed that, compared to the control group E-6d, differentially expressed genes (DEGs) in the CaS-treated group S-6d were significantly enriched in starch and sucrose metabolism, secondary metabolite biosynthesis, general metabolic pathways, and cysteine and methionine metabolism. Subsequent filtering based on expression levels yielded 80 significantly differentially expressed target genes. After removing redundant gene entries, 29 unique DEGs were selected for detailed analysis. As shown in Fig. 7E, the heatmap on the left illustrates significant downregulation of these 29 genes in the CaS-treated group (S-6d) relative to E-6d. The Sankey bubble plot on the right indicates that these genes are predominantly enriched in three KEGG pathways: ethylene biosynthesis-related genes are enriched in the cysteine and methionine metabolism pathway, starch degradation-related genes cluster in the starch and sucrose metabolism pathway, and cell wall hydrolysis-related genes are mainly distributed in general metabolic pathways. These results demonstrate that CaS treatment downregulates the expression of genes involved in ethylene biosynthesis (e.g., ACO, ACS), starch degradation (amylases), and cell wall degradation (cellulases and.

pectinases), thereby inhibiting their enzymatic activities and effectively delaying the postharvest ripening process of banana fruit. This transcriptional regulation is consistent with and corroborates the experimental data presented earlier.

4. Conclusion

This study systematically elucidates the regulatory mechanism of CaS as a sustained-release H₂S donor in postharvest banana ripening. CaS Powder undergoes a solid-liquid-gas multiphase reaction with environmental moisture and carbon dioxide, controlled by diffusion and product layer formation, enabling continuous and stable H₂S release over 48 h rather than instantaneous discharge, thereby preventing potential harm from high H2S concentration and achieving effective sustained delivery. CaS treatment significantly maintains the firmness of banana peel and pulp by downregulating key genes involved in the ethylene biosynthesis pathway, including MaACO1, MaACO4, MaACO13, MaACS1, and MaACS12 to varying degrees, thus markedly suppressing ethylene production and delaying fruit ripening. Meanwhile, CaS also significantly inhibited the transcription of starch degradation-related genes and cell-wall-modifying genes, delaying starch breakdown and cell wall hydrolysis. These multi-level regulatory effects synergistically contributed to the substantial delay of postharvest banana ripening. When shortening CaS application time from 10 days to 4 days, the shelf life of banana fruits was extended to 14 days without hindering the normal ripening progress, and retained higher soluble sugar content in the pulp at late stage of storage, demonstrating effective maintenance of fruit quality.

CRediT authorship contribution statement

Hong Xu: Writing – original draft, Validation, Investigation. Xueting Bi: Methodology, Investigation. Junjie Xing: Methodology, Investigation. Mengqian Guo: Methodology, Investigation. Haoran Zhang: Writing – original draft. Xuejie Zhang: Writing – original draft. Wei Li: Writing – review & editing, Supervision, Data curation. Bingfu Lei: Supervision, Project administration, Funding acquisition.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This work received support from the National Natural Science Foundations of China (12274144 and 52102042), Guangdong Provincial Special Fund for Modern Agriculture Industry Technology Innovation Teams (No. 2023KJ122), and Guangdong Provincial Science, Technology Project (No. 2020A1414010049).

Footnotes

Appendix A

Supplementary data to this article can be found online at https://doi.org/10.1016/j.fochms.2025.100297.

Contributor Information

Wei Li, Email: liwei@scau.edu.cn.

Bingfu Lei, Email: tleibf@scau.edu.cn.

Appendix A. Supplementary data

Supplementary material 1

mmc1.docx (8.8MB, docx)

Supplementary material 2

mmc2.docx (24KB, docx)

Data availability

No data was used for the research described in the article.

References

  1. Adiletta G., Di Matteo M., Petriccione M. Multifunctional role of chitosan edible coatings on antioxidant systems in fruit crops: A review. International Journal of Molecular Sciences. 2021;22:2633. doi: 10.3390/ijms22052633. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Al-Dairi M., Pathare P.B., Al-Yahyai R., Jayasuriya H., Al-Attabi Z. Postharvest quality, technologies, and strategies to reduce losses along the supply chain of banana: A review. Trends in Food Science & Technology. 2023;134:177–191. doi: 10.1016/j.tifs.2023.03.003. [DOI] [Google Scholar]
  3. Bapat V.A., Trivedi P.K., Ghosh A., Sane V.A., Ganapathi T.R., Nath P. Ripening of fleshy fruit: Molecular insight and the role of ethylene. Biotechnology Advances. 2010;28:94–107. doi: 10.1016/j.biotechadv.2009.10.002. [DOI] [PubMed] [Google Scholar]
  4. Bernal L., Lujan-Soto E., Fajardo-Hernandez C.A., Coello P., Figueroa M., Martinez-Barajas E. Starch degradation in the bean fruit pericarp is characterized by an increase in maltose metabolism. Physiologia Plantarum. 2022;174 doi: 10.1111/ppl.13836. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Bora D., Roy K., Mahanta P., Barbora L. Hydrogen sulfide removal from biogas using biomass-derived naturally alkaline biochars: Performance analysis and kinetics. Journal of Material Cycles and Waste Management. 2024;26:1544–1556. doi: 10.1007/s10163-024-01908-8. [DOI] [Google Scholar]
  6. Bramlage W.J. Chilling injury of crops of temperate origin. Hortscience. 1982;17:165–168. doi: 10.21273/HORTSCI.17.2.165. [DOI] [Google Scholar]
  7. Brummell D.A. Cell wall disassembly in ripening fruit. Functional Plant Biology. 2006;33:103–119. doi: 10.1071/FP05234. [DOI] [PubMed] [Google Scholar]
  8. Cefola M., Pace B. Advances postharvest preservation technology. Foods. 2023;12:1664. doi: 10.3390/foods12081664. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Chen L., Zhong H., Kuang J., Li J., Lu W., Chen J. Validation of reference genes for rt-qpcr studies of gene expression in banana fruit under different experimental conditions. Planta. 2011;234:377–390. doi: 10.1007/s00425-011-1410-3. [DOI] [PubMed] [Google Scholar]
  10. Cordenunsi-Lysenko B.R., Oliveira Nascimento J.R., Castro-Alves V.C., Purgatto E., Fabi J.P., Goncalves Peroni-Okyta F.H. The starch is (not) just another brick in the wall: The primary metabolism of sugars during banana ripening. Frontiers in Plant Science. 2019;10:391. doi: 10.3389/fpls.2019.00391. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Deng F., Li Q., Chen H., Zeng Y., Li B., Zhong X., Wang L., Ren W. Relationship between chalkiness and the structural and thermal properties of rice starch after shading during grain-filling stage. Carbohydrate Polymers. 2021;252 doi: 10.1016/j.carbpol.2020.117212. [DOI] [PubMed] [Google Scholar]
  12. Deng P., Zhang Y., Deng Q., Sun Y., Li Y., Wang Z., Jiang F. Multifunctional sodium alginate-based self-healing edible cross-linked coating for banana preservation. Food Hydrocolloids. 2025;151 doi: 10.1016/j.foodhyd.2025.111047. [DOI] [Google Scholar]
  13. Elsabagh R., Ibrahim S.S.S., Abd-Elaaty E.M.M., Abdeen A., Rayan A.M.M., Ibrahim S.F.F.…Morsy M.K.K. Chitosan edible coating: A potential control of toxic biogenic amines and enhancing the quality and shelf life of chilled tuna filets. Frontiers in Sustainable Food Systems. 2023;7 doi: 10.3389/fsufs.2023.1177010. [DOI] [Google Scholar]
  14. Foster J.C., Carrazzone R.J., Spear N.J., Radzinski S.C., Arrington K.J., Matson J.B. Tuning h2s release by controlling mobility in a micelle core. Macromolecules. 2019;52:1104–1111. doi: 10.1021/acs.macromol.8b02315. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Ge Y., Hu K., Wang S., Hu L., Chen X., Li Y.…Zhang H. Hydrogen sulfide alleviates postharvest ripening and senescence of banana by antagonizing the effect of ethylene. PLoS One. 2017;12 doi: 10.1371/journal.pone.0180113. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Gil M.I., López-Gálvez F., Andújar S., Moreno M., Allende A. Disinfection by-products generated by sodium hypochlorite and electrochemical disinfection in different process wash water and fresh-cut products and their reduction by activated carbon. Food Control. 2019;100:46–52. doi: 10.1016/j.foodcont.2018.12.050. [DOI] [Google Scholar]
  17. Gwanpua S.G., Van Buggenhout S., Verlinden B.E., Christiaens S., Shpigelman A., Vicent V., Kermani Z.J., Nicolai B.M., Hendrickx M., Geeraerd A. Pectin modifications and the role of pectin-degrading enzymes during postharvest softening of jonagold apples. Food Chemistry. 2014;158:283–291. doi: 10.1016/j.foodchem.2014.02.138. [DOI] [PubMed] [Google Scholar]
  18. Hansen J., Møller I. Percolation of starch and soluble carbohydrates from plant tissue for quantitative determination with anthrone. Analytical Biochemistry. 1975;68:87–94. doi: 10.1016/0003-2697(75)90682-X. [DOI] [PubMed] [Google Scholar]
  19. Hu X., Kuang S., Zhang A., Zhang W., Chen M., Yin X., Chen K. Characterization of starch degradation related genes in postharvest kiwifruit. International Journal of Molecular Sciences. 2016;17:2112. doi: 10.3390/ijms17122112. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Karthiayani A., Mathad P.F., Varadharaju N., Kennedy Z.J. Studies on preservation of banana stored under modified atmospheric conditions using diffusion channel. Journal of Food Science and Technology-Mysore. 2006;43:314–317. doi: 10.5555/20063110138. [DOI] [Google Scholar]
  21. Kötting O., Pusch K., Tiessen A., Geigenberger P., Steup M., Ritte G. Identification of a novel enzyme required for starch metabolism in arabidopsis leaves.: The phosphoglucan, water dikinase. Plant Physiology. 2005;137:242–252. doi: 10.1104/pp.104.055954. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Li R., Wang Y., Li W., Shao Y. Comparative analyses of ripening, texture properties and cell wall composition in three tropical fruits treated with 1-methylcyclopropene during cold storage. Horticulturae. 2023;9:126. doi: 10.3390/horticulturae9020126. [DOI] [Google Scholar]
  23. Li W., Kaminski Schierle G.S., Lei B., Liu Y., Kaminski C.F. Fluorescent nanoparticles for super-resolution imaging. Chemical Reviews. 2022;122:12495–12543. doi: 10.1021/acs.chemrev.2c00050. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Li W., Lin J., Huang W., Wang Q., Zhang H., Zhang X., Zhuang J., Liu Y., Qu S., Lei B. Delivery of luminescent particles to plants for information encoding and storage. Light: Science & Applications. 2024;13:217. doi: 10.1038/s41377-024-01518-x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Li W., Wang Y., Wang B., Lu K., Cai W., Lin J., Huang X., Zhang H., Zhang X., Liu Y., Liang Y., Lei B., Qu S. Enhanced light-harvesting and energy transfer in carbon dots embedded thylakoids for photonic hybrid capacitor applications. Angewandte Chemie International Edition. 2024;63 doi: 10.1002/anie.202308951. [DOI] [PubMed] [Google Scholar]
  26. Liu J., Liu M., Jia C., Zhang J., Miao H., Wang J., Zhang J., Wang Z., Xu B., Li X., Jin Z. Elucidating the mechanism of magwd1-mediated starch degradation cooperatively regulated by mamads36 and mamads55 in banana. Postharvest Biology and Technology. 2021;179 doi: 10.1104/pp.104.055954. [DOI] [Google Scholar]
  27. Liu P. Uncovering the mechanism of banana “green ripening”. The Plant Cell. 2023;35:1294–1295. doi: 10.1093/plcell/koad048. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Payasi A., Mishra N.N., Chaves A.L.S., Singh R. Biochemistry of fruit softening: An overview. Physiology and Molecular Biology of Plants : An International Journal of Functional Plant Biology. 2009;15:103–113. doi: 10.1007/s12298-009-0012-z. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Pesek S., Lehene M., Branzanic A.M.V., Silaghi-Dumitrescu R. On the origin of the blue color in the iodine/iodide/starch supramolecular complex. Molecules. 2022;27:8974. doi: 10.3390/molecules27248974. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Quoc L.P.T., An H.T.T., Lam L.T., Ly L.T.H., Suong N.T.T. The effects of ethephon on the ripening of vietnamese latundan bananas (musa sapientum) Emirates Journal of Food and Agriculture. 2014;26:229–237. doi: 10.9755/ejfa.v26i3.15853. [DOI] [Google Scholar]
  31. Rahman F.U., Zhou Y., Liang P., Zheng W., Wu Z., Wu B., Chen W., Li X., Zhu X. The effect of 1-mcp on fruit ripening and glycometabolism in banana. Scientia Horticulturae. 2024;338 doi: 10.1016/j.scienta.2024.113824. [DOI] [Google Scholar]
  32. Ren Y., Li B., Jia H., Yang X., Sun Y., Shou J., Jiang G., Shi Y., Chen K. Comparative analysis of fruit firmness and genes associated with cell wall metabolisms in three cultivated strawberries during ripening and postharvest. Food Quality and Safety. 2023;7:fyad20. doi: 10.1093/fqsafe/fyad020. [DOI] [Google Scholar]
  33. Ritte G., Lloyd J.R., Eckermann N., Rottmann A., Kossmann J., Steup M. The starch-related r1 protein is an α-glucan, water dikinase. Proceedings of the National Academy of Sciences of the United States of America. 2002;99:7166–7171. doi: 10.1073/pnas.062053099. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Santelia D., Zeeman S.C. Progress in arabidopsis starch research and potential biotechnological applications. Current Opinion in Biotechnology. 2011;22:271–280. doi: 10.1016/j.copbio.2010.11.014. [DOI] [PubMed] [Google Scholar]
  35. Satekge T.K., Magwaza L.S. Postharvest application of 1-methylcyclopropene (1-mcp) on climacteric fruits: Factors affecting efficacy. International Journal of Fruit Science. 2022;22:595–607. doi: 10.1080/15538362.2022.2085231. [DOI] [Google Scholar]
  36. Shi Y., Li B., Grierson D., Chen K. Insights into cell wall changes during fruit softening from transgenic and naturally occurring mutants. Plant Physiology. 2023;192:1671–1683. doi: 10.1093/plphys/kiad128. [DOI] [PMC free article] [PubMed] [Google Scholar]
  37. Sinanoglou V.J., Tsiaka T., Aouant K., Mouka E., Ladika G., Kritsi E., Konteles S.J., Ioannou A., Zoumpoulakis P., Strati I.F., Cavouras D. Quality assessment of banana ripening stages by combining analytical methods and image analysis. Applied Sciences-Basel. 2023;13:3533. doi: 10.3390/app13063533. [DOI] [Google Scholar]
  38. Su-Mon M., Asrey R., Meena N.K., Sethi S. Attenuating sugar spot and retaining quality of banana fruits by combined use of hot water and calcium lactate during storage. Food Science and Technology International. 2024;30:49–60. doi: 10.1177/10820132221132911. [DOI] [PubMed] [Google Scholar]
  39. Tipu M.M.H., Sherif S.M. Ethylene and its crosstalk with hormonal pathways in fruit ripening: Mechanisms, modulation, and commercial exploitation. Frontiers in Plant Science. 2024;15 doi: 10.3389/fpls.2024.1475496. [DOI] [PMC free article] [PubMed] [Google Scholar]
  40. Wan C.Y., Wilkins T.A. A modified hot borate method significantly enhances the yield of high-quality rna from cotton (gossypium hirsutum l.) Analytical Biochemistry. 1994;223:7–12. doi: 10.1006/abio.1994.1538. [DOI] [PubMed] [Google Scholar]
  41. Wang Y., Lu W., Jiang Y., Luo Y., Jiang W., Joyce D. Expression of ethylene-related expansin genes in cool-stored ripening banana fruit. Plant Science. 2006;170:962–967. doi: 10.1016/j.plantsci.2006.01.001. [DOI] [Google Scholar]
  42. Wu M., Luo Z., Cao S. Promoter variation of the key apple fruit texture related gene mdpg1 and the upstream regulation analysis. Plants-Basel. 2023;12:1452. doi: 10.3390/plants12071452. [DOI] [PMC free article] [PubMed] [Google Scholar]
  43. Xiao X., Fu Z., Zhu Z., Zhang X. Improved preservation process for table grapes cleaner production in cold chain. Journal of Cleaner Production. 2019;211:1171–1179. doi: 10.1016/j.jclepro.2018.11.279. [DOI] [Google Scholar]
  44. Xiao Y., Kuang J., Qi X., Ye Y., Wu Z., Chen J., Lu W. A comprehensive investigation of starch degradation process and identification of a transcriptional activator mabhlh6 during banana fruit ripening. Plant Biotechnology Journal. 2018;16:151–164. doi: 10.1111/pbi.12756. [DOI] [PMC free article] [PubMed] [Google Scholar]
  45. Yu Z., Yuan R., Yang J., Pan Y. Hydrogen sulfide delays softening of banana fruit by inhibiting cell wall polysaccharides disassembly. International Journal of Food Science and Technology. 2023;58:5236–5246. doi: 10.1111/ijfs.16625. [DOI] [Google Scholar]
  46. Zeeman S.C., Kossmann J., Smith A.M. Starch: Its metabolism, evolution, and biotechnological modification in plants. Annual Review of Plant Biology. 2010;61:209–234. doi: 10.1146/annurev-arplant-042809-112301. [DOI] [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

Supplementary material 1

mmc1.docx (8.8MB, docx)

Supplementary material 2

mmc2.docx (24KB, docx)

Data Availability Statement

No data was used for the research described in the article.

Articles from Food Chemistry: Molecular Sciences are provided here courtesy of Elsevier

RESOURCES