Abstract
Freshly harvested apple fruits cv.‘Royal Delicious’ were subjected to Surface coating with 1, 1.5, 2% neem oil (Azadirachta indica) and 10, 15, 20% marigold flower (Tagetes erectus) extracts with pre cooling on apple storage quality was tested. Then the fruits were analyzed for physicochemical and physiological characters such as loss in weight, fruit firmness, total soluble solids (TSS) content, titratable acidity (TA), pH, reducing sugar contents, pectin, total anthocyanin, polygalacturonase (PG) activity and fruit spoilage. The results revealed that, the 1.5–2% concentration of neem oil as a surface coating along with pre-cooling was the most effective by retaining better physiochemical characteristics, in addition, significantly lowering disease incidence. Similarly, packaging of fruits with corrugated fiber board (CFB) boxes + paper mould trays, CFB + Polyethylene (PE) liners and shrink wrapped tray packing during storage (18–25 °C and 65–75% RH), revealed that 2% neem oil surface coating with shrink wrap tray packing resulted the better retention of storage life and, whereas, the treatment effect on physico-chemical characteristics of fruits were significant (p < 0.05). However, the treatment effect was statistically at par with the marigold extract application with shrink wrapped tray packing in pre cooled fruits (10–15 °C, 70–75% RH) during ambient storage (18–25 ° C, 65–75% RH).
Keywords: Apple, Pre-cooling, Surface coatings, Neem oil, Marigold flower extracts, Storage
Apple (Malus domestica) is commercially cultivated in Jammu and Kashmir, Himachal Pradesh, Uttrakhand having 99% of the total production accounting for about 2.5% of world apple production. (Anon 2005). The production of fruit 2006–07 as per the data available with the National Horticulture Board (NHB) is 58.92 million tones and latest information indicates that 30% of all fruits produced (roughly worth Rs 13,600 cores) are lost due to mismanagement. In case of apple, the loss percentage was 10–25% from the total production (Anon 2007). Due to its tendency towards fast ripening and texture breakdown, apple is difficult to keep well for longer period of time. Number of workers has made attempts to enhance the storage life of apple using different substances at the pre or postharvest stages. However, most of the synthetic chemicals being used for crop protection are reported to pose a serious threat to human health and have residual effect, beside being costly, therefore, all these factors have led to research for safer and more competitive alternatives. However, it has been reported that various botanical extracts such as neem leaf extracts, neem kernel oil, Malia leaf extracts, Mentha leaf extracts, onion extracts are residue free and safe from consumption point of view as compared to fungicides that are highly toxic to living beings. These extracts have a number of active ingredients that help in checking decay losses in fruits that are caused by the fungal infection (Bhowmick and Choudhary 1992). Kleeberg (1996); Deshmukh et al (1992) have reported that azadirachtin, camacin, menthol and euglone were the active compounds in neem, melia, mentha and walnut leaves, respectively; and that these substances strengthened the pectin molecule by eliminating the chances of methyl group removal from the alpha-galactouronic acid residue of pectin; and therefore, helped in lowering the breakdown of pectin during storage. The distinguishing feature of the Tagetes genus is the presence of conspicuous brown black glands, which contain highly odoriferous components (Rodriguez and Mabery 1977).Various Tagetus oils analyzed by GC-MS were shown to contain limonene, tagetone, dihydrotagetone, ocimene, ocimenone and α-terpinoles (Vasudevan et al 1997); and, as such, who have further reported that the extracts from Tagetes, Mentha and Pelargonium were significantly effective in reducing stem end rot of pear (Pyrus communis); and that the test plant extracts provided better protection rather than eradicants.
Also, pre-cooling facilitates the good temperature management for prevention of ripening and that the on set of senescence is effectively delayed by maintaining low product temperature helps in reducing water loss and subsequent, product shriveling when combine its with packaging (Kaynas and Sivritepe 1995).
Therefore the present investigation was conducted to determine the effect of pre-cooling, in combination with the use natural extracts as fruit coating and different packages to enhance the storage quality of apple cv. ‘Royal Delicious’ under ambient storage.
Materials and methods
Royal Delicious apple fruits were procured from a well maintained commercial orchard situated at an elevation of 5,500 feet above meen sea level in village Chiathla (Kotkhai), District Shimla, Himachal Pradesh, India. The total number of fruits for this experiment was divided in to two sets. Before transportation one set was subjected to pre-cooling for 30 minutes at 10–15 °C, 70–75% RH in orchard itself by using low-pressure container which has been specially designed by modifying the head of an autoclave of 20 L capacity provided with a glass flat bottom flask designed as a humidifier. The pressure was maintained at 500 mmHg. The other set of fruit was not pre-cooled. Fruit from both the sets were subjected to postharvest treatments.
Preparation of solutions and treatment of fruits
The flower extract was prepared by drying of flowers under shade followed by grinding them to powder form in an electric blender. Aqueous solution was prepared by soaking a known weight of the powder material in an equal quantity of water and keeping it over night. The extract was separated with the help of muslin cloth and it was considered to be of 100 percent strength. It was diluted by adding appropriate quantity of distilled water to make up the desired concentrations. 2.0 % guar gum was added to make a coating solution. The solutions of neem oil was prepared by proper mixing of oil with distilled water emulsifying with guar gum on % weight basis (2 ml oil/ 100 ml of distilled water with 2 % guar gum). For the surface application of coating treatments, both the pre-cooled and non-pre-cooled fruits were used. After washing and air-drying, these fruits were subjected to different postharvest coating treatments with marigold extract and neem oil by dipping them for 5 minutes.
The pre-cooled as well as not pre-cooled fruits were dipped in 10,15, 20% marigold flower extract (T1,T2,T3) and 1, 1.5, 2% of neem oil (T4,T5,T6) for 5 minutes and control (T7) was without any treatment. Then the fruits were packed in 3 types of packages; shrink wrapped tray packing (P1), Paper mould tray + CFB carton (P2), LDPE (150 gauge) liner + CFB carton (P3).
Fruit storage
Fruits from all the treatments and replicates were stored at ambient (18–25 °C, 65–75% RH) storage and the observation with regard to the physiological and physico-chemical characteristics of fruits were recorded at an interval of 15 days for 45 days of storage.
Physical characteristics
Pre-weighed fruit samples were weighed on a top loading balance (OHAUS, model ARA 520, New Jersey, 07058, USA) after each storage interval. The losses in weight during storage were expressed as % of initial weight on each sample date. Fruit firmness was measured with Effigi Penetrometer with 11 mm probe tip (model FT 327,Effegi Alfonsine, Italy), which recorded the pressure required to force a plunger of 11 mm diameter into pared flesh of fruit samples.
Physico-chemical characteristics
The total soluble solids (TSS) content in fruit juice was recorded with the help of hand refractometer (ATAGO, model: HR-5[0–90%], Japan) by squeezing the juice with cotton wool on to the cleaned sensor and reading was reported as ºBrix. pH, of a known amount of fresh and homogenized fruit juice in a 100 ml beaker was recorded with a digital pH meter (Thermoorion, model 230A+, 9157 BN, Witchford, England) after standardizing the pH meter with buffer solutions of pH 4 and 7 (Ranganna 1986). Titratable acidity was determined as per Horwitz (1980) method. A known weight of fruit sample was crushed and taken in to 250 ml volumetric flask and the volume was made up. After filtration, 10 ml of filtrate was titrated against 0.1 N NaOH using phenolphthalein as indicator. The reducing sugar content was estimated by Lane and Eynon’s volumetric method (Horwitz 1980). Pectin content was determined by Carre and Hayne’s methods as described by Ranganna (1986) and expressed as percent calcium pectate. Polygalacturonase activity (PG) was determined by the method described by Mahadevan and Sridhar (1982). The enzyme action mixture consisted of enzyme extract (2 ml) which was prepared by crushing fruit flesh, 4 ml of sodium polypectate substrate (by dissolving 750 mg of the sodium polypectate in 100 ml of acetate buffer, pH 5.2, heated to 50–60 °C and placed in a blender for mixing) and 1 ml of acetate buffer. Using Ostwald-type viscometer the content was mixed by gently drawing air through the large arm of the viscometer and suction was applied through the small arm of the viscometer and initial efflux time of mixture was determined. After 16 hours, again the efflux time of the mixture was measured. Anthocyanin pigments of apple fruit skin were extracted with solvent mixture of acidic ethyl alcohol (Ranganna 1986) and the intensity of colour was measured through 535 nm wavelength in a spectrophotometer against blank. Spoilage of fruits due to fungal rots was calculated by adding up the number of fruits spoiled on successive storage interval and calculating their percentage on the basis of number of fruits stored initially.
Statistical analysis
The experiments were carried out as completely randomized design (CRD) with three replicates. Each replicate consisted 25 fruits and 5 fruits from each replicate were used for analysis. Mean separation was done by Least Significant Different (LSD) (at α = 0.05).
Results and discussion
Progressive and significant increase in physiological weight loss of fruits occurred in each treatments and pre-cooled fruits exhibited relatively slower loss in weight on the corresponding dates as compared to the non-pre-cooled (Table 1).This may be due to the fact that loss of moisture from pre-cooled commodities is slower if higher relative humidity is maintained in the storage atmosphere. Such conditions can easily be achieved by lowering the temperature as the storage environment tends to be more saturated simply by reduction in temperature (Lurie and Ben 1990).The results revealed that coating of fruits with 2 % neem oil (T6) and 1.5 % neem oil (T5) with shrink wrap tray packing had the minimum physiological weight loss (2.4–2.5%), possibly due to reduction of both the rate of metabolism and also prevents water loss (Bhardwaj and Sen 2003).
Table 1.
Effect of pre cooling, fruit coating and packaging on the physiological weight loss (%) of Royal delicious apples during storage at 18–25 °C for 45 days
| T | ||||||
|---|---|---|---|---|---|---|
| C1 | C2 | |||||
| P | P1 | P2 | P3 | P1 | P2 | P3 |
| T1 | 4.7 | 5.4 | 5.8 | 4.7 | 5.7 | 6.0 |
| T2 | 5.0 | 5.3 | 5.7 | 4.4 | 5.5 | 5.9 |
| T3 | 3.1 | 4.3 | 4.7 | 3.0 | 4.0 | 4.7 |
| T4 | 4.4 | 4.7 | 5.2 | 3.7 | 4.9 | 5.4 |
| T5 | 2.5 | 3.5 | 4.1 | 2.2 | 3.4 | 4.0 |
| T6 | 2.4 | 3.8 | 3.8 | 2.0 | 3.6 | 3.8 |
| T7 | 5.5 | 5.9 | 6.2 | 5.5 | 6.3 | 6.5 |
CD0.05 C = 0.002, CxPxT =0.008
T treatments; C1 pre-cooled; C2 without pre cooled; (P1) shrink wrapped tray packing; (P2) Paper mould tray + CFB carton; (P3) LDPE (150 gauge) liner + CFB carton; marigold flower extract:T1−10%, T2−15%, T3−20% ;neem oil: T4−1%, T5−1.5%, T6−2%, T7− control. (p < 0.05), n = 3
The decline in fruit firmness (Table 2) was significantly lower in pre-cooled fruits whereas, 2 % neem oil (T6) coupled with shrink wrap tray packing was the most effective treatment in retaining fruit firmness (66.4 N) with respect to pre-cooled fruits. However, the possibility of achieving a modified atmosphere condition has been put forward as one of the advantages to be gained by the use of plastic films. This technique leads to reduction of metabolic rates, and prevention of water loss, which is further facilitated by the reduction in temperature (Singh and Chauhan 1986). Similar observations were recorded by Anzueto and Rizvi (1985), wherein at 21 °C heat shrinkable polymer packed apple fruits reached maximum acceptable conditions at 6 week of storage against the shelf life extension of 3–4 weeks over non-packed controls.
Table 2.
Effect of pre cooling, fruit coating and packaging on the fruit firmness (N) of Royal delicious apples during storage at 18–25 °C for 45 days
| T | ||||||
|---|---|---|---|---|---|---|
| C1 | C2 | |||||
| P | P1 | P2 | P3 | P1 | P2 | P3 |
| T1 | 55.3 | 49.5 | 51.7 | 52.4 | 45.1 | 47.2 |
| T2 | 61.6 | 51.0 | 55.6 | 57.4 | 51.7 | 54.5 |
| T3 | 64.2 | 62.8 | 62.4 | 60.4 | 56.5 | 57.7 |
| T4 | 64.6 | 59.6 | 63.8 | 61.0 | 56.9 | 56.8 |
| T5 | 65.0 | 61.4 | 62.9 | 60.9 | 57.4 | 59.2 |
| T6 | 66.4 | 60.7 | 66.1 | 61.9 | 58.5 | 61.1 |
| T7 | 47.8 | 39.5 | 42.0 | 44.0 | 35.8 | 39.1 |
Initial value 76.21
CD0.05 C = 0.01, CxPxT =0.02
T treatments; C1 pre-cooled; C2 without pre cooled; (P1) shrink wrapped tray packing; (P2) Paper mould tray + CFB carton; (P3) LDPE (150 gauge) liner + CFB carton; marigold flower extract:T1−10%, T2−15%, T3−20% ;neem oil: T4−1%, T5−1.5%, T6−2%, T7− control. (p < 0.05), n = 3
Pre-cooled fruits retained maximum TA content whereas, minimum fruit juice pH (4.0) was recorded with respect to pre-cooled fruits packed in shrink wrapped tray package, with treatment T5 and T6 (Table 3). The lower level of titratable acidity content and higher pH was recorded by control (T7). The faster rate of decline in acidity in control fruits could be due to the faster metabolic reactions occurring within them. The application of different coating treatments may also slow down the metabolism of fruits as these have been reported to maintain higher CO2 and lower O2 levels inside the coated fruits (Kader et al 1989), and this might explain the retention of higher acid levels and, consequently, lower pH values . Among the metabolic reactions, respiration is an important process, which may utilize organic acids as a substrate during the peak energy requirement of fruits, which usually coincides with ripening leading to a decrease in pH during prolonged storage (Sonkar and Ladaniya 1999).
Table 3.
Effect of pre cooling, fruit coating and packaging on the titratable acidity (% malic acid) and pH of Royal delicious apples during storage at 18–25 °C for 45 days
| Titratable acidity (% malic acid) | ||||||
|---|---|---|---|---|---|---|
| T | ||||||
| (C1) | (C2) | |||||
| (P) | P1 | P2 | P3 | P1 | P2 | P3 |
| T1 | 0.3 | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 |
| T2 | 0.3 | 0.2 | 0.3 | 0.3 | 0.2 | 0.2 |
| T3 | 0.3 | 0.2 | 0.3 | 0.3 | 0.2 | 0.2 |
| T4 | 0.3 | 0.3 | 0.3 | 0.3 | 0.2 | 0.2 |
| T5 | 0.3 | 0.3 | 0.3 | 0.3 | 0.2 | 0.3 |
| T6 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 |
| T7 | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 |
| Initial value: 0.39 | ||||||
| CD0.05 C = 0.01, CxPxT = 0.02 | ||||||
| pH | ||||||
| T1 | 4.4 | 4.5 | 4.2 | 4.5 | 4.6 | 4.6 |
| T2 | 4.3 | 4.5 | 4.5 | 4.5 | 4.6 | 4.6 |
| T3 | 4.1 | 4.3 | 4.2 | 4.3 | 4.4 | 4.4 |
| T4 | 4.3 | 4.4 | 4.3 | 4.6 | 4.6 | 4.6 |
| T5 | 4.0 | 4.1 | 4.2 | 4.2 | 4.2 | 4.4 |
| T6 | 4.0 | 4.3 | 4.3 | 4.2 | 4.5 | 4.2 |
| T7 | 4.6 | 4.8 | 4.7 | 4.8 | 4.8 | 4.5 |
Initial value 3.3
CD0.05 C = 0.01, CxPxT = 0.05
T treatments; C1 pre-cooled; C2 without pre cooled; (P1) shrink wrapped tray packing, (P2) Paper mould tray + CFB carton; (P3) LDPE (150 gauge) liner + CFB carton ; marigold flower extract:T1−10%, T2−15%, T3−20% ;neem oil: T4−1%, T5−1.5%, T6−2%, T7− control. (p < 0.05), n = 3
Maximum TSS content 16.2°B was recorded in response to coating with 1.5% neem oil with pre-cooled fruits whereas, the maximum reducing sugar contents, (8.4–8.5%) was recorded in (1.5–2.0%) neem oil treatments, when the fruits packed in shrink-wrap tray package and the minimum TSS content was recorded by control (Table 4). The increase in TSS and sugar content may be due to the hydrolysis of insoluble polysaccharides into simple sugars. The increase in TSS and sugar contents in control fruits may be due to the higher physiological weight loss in these fruits; and, as a result of which, there might have been an increase in the concentration of sugars and total soluble solids. At the same time, such changes are expected to be slower and more gradual when the metabolism of the commodity is slowed down by the application of treatments so adopted under experimentation coupled with precooling. So, with the decrease in metabolism, the rate of utilization of stored metabolites is also slowed down; and, thereby, resulting in retention of higher levels of these constituents. These findings are further supported by the observations of Singh and Mohammed (1997).
Table 4.
Effect of pre cooling, fruit coating and packaging on the total soluble solids(B°) and Reducing sugar content (%) of Royal delicious apples during storage at 18–25 °C for 45 days
| Total soluble solids(B°) | ||||||
|---|---|---|---|---|---|---|
| T | ||||||
| (C1) | (C2) | |||||
| (P) | P1 | P2 | P3 | P1 | P2 | P3 |
| T1 | 14.2 | 13.8 | 13.9 | 13.8 | 13.8 | 14.0 |
| T2 | 14.9 | 14.6 | 14.8 | 14.7 | 14.5 | 14.5 |
| T3 | 15.1 | 14.9 | 15.2 | 14.9 | 14.6 | 14.6 |
| T4 | 15.9 | 15.4 | 15.7 | 15.8 | 15.1 | 15.7 |
| T5 | 16.2 | 15.9 | 15.9 | 15.7 | 15.5 | 17.1 |
| T6 | 16.1 | 15.2 | 16.1 | 16.2 | 15.2 | 15.8 |
| T7 | 13.8 | 13.3 | 13.8 | 13.7 | 12.9 | 13.5 |
| Initial value: 10.24 | ||||||
| CD0.05 C = 0.01 CxPxT = 0.02 | ||||||
| Reducing sugar content (%) | ||||||
| T1 | 7.3 | 7.0 | 7.1 | 7.4 | 7.0 | 7.2 |
| T2 | 8.2 | 7.9 | 7.9 | 8.1 | 7.8 | 7.8 |
| T3 | 8.3 | 8.0 | 8.1 | 8.3 | 7.8 | 8.1 |
| T4 | 8.1 | 7.8 | 7.9 | 7.9 | 7.6 | 7.7 |
| T5 | 8.5 | 8.2 | 8.4 | 8.2 | 7.9 | 8.2 |
| T6 | 8.4 | 8.1 | 8.3 | 8.3 | 8.0 | 8.2 |
| T7 | 7.1 | 6.9 | 7.1 | 7.1 | 6.8 | 6.9 |
Initial value 5.54
CD0.05 C = 0.01, CxPxT = 0.02
T treatments; C1 pre-cooled; C2 without pre cooled; (P1) shrink wrapped tray packing, (P2) Paper mould tray + CFB carton; (P3) LDPE (150 gauge) liner + CFB carton ; marigold flower extract:T1−10%, T2−15%, T3−20% ;neem oil: T4−1%, T5−1.5%, T6−2%, T7− control. (p < 0.05), n = 3
2% neem oil showed the higher value of total anthocyanin content (18.5 mg/100 g with shrink wrap tray packing with pre cooling. A continuous decrease in total anthocyanin content observed in all the treatments, whereas pre-cooling, coating and shrink wrapped tray packing was effective for reduction in losses of pigment and this may possibly be due to the delayed senescence of tissues which involve the degradation of these pigments (Table 5).
Table 5.
Effect of pre cooling, fruit coating and packaging on the total anthocyanin content (mg/100 g) of Royal delicious apples during storage at 18–25 °C for 45 days
| T | ||||||
|---|---|---|---|---|---|---|
| C1 | C2 | |||||
| P | P1 | P2 | P3 | P1 | P2 | P3 |
| T1 | 14.6 | 14.1 | 14.3 | 14.1 | 13.2 | 13.2 |
| T2 | 15.2 | 14.3 | 14.2 | 14.6 | 13.8 | 13.1 |
| T3 | 16.7 | 15.4 | 16.2 | 16.2 | 14.7 | 15.4 |
| T4 | 18.2 | 16.5 | 17.3 | 17.4 | 15.4 | 16.3 |
| T5 | 18.2 | 18.1 | 17.6 | 17.5 | 17.1 | 16.7 |
| T6 | 18.5 | 16.6 | 18.3 | 17.9 | 16.3 | 17.5 |
| T7 | 13.0 | 13.3 | 13.5 | 12.5 | 12.3 | 12.6 |
Initial value 30.4
CD0.05 C = 0.02, CxPxT = 0.11
T treatments; C1 pre-cooled; C2 without pre cooled; (P1) shrink wrapped tray packing; (P2) Paper mould tray + CFB carton; (P3)-LDPE (150 gauge) liner + CFB carton ; marigold flower extract:T1−10%, T2−15%, T3−20% ;neem oil: T4−1%, T5−1.5%, T6−2%,T7− control. (p < 0.05), n = 3
The pectin content, in general, declined in all treatments. However, (1.5–2.0%) neem oil treatment (T6) retained maximum pectin content, (1.3%), (Table 6). The decrease in pectin content in all treatments at the end of storage might be the result of pectolytic enzymes activity on natural pectin in the fruits (Nara et al 2001). According to present findings, neem oil exhibited better retention of PG over different concentration of marigold flower extracts, as well as the pre-cooling and packaging also showed a marked effect on reduction of fruit softening during storage. Gupta and Bhandari (1974) examine the composition and physio-chemical properties of Tagatus erecta flowering tops and reported the precence of d-limonene, ocemene, d-linalool, α-d-phellandrene, tagetone. Baslas and Singh (1980) reported the presence of α-pinene, β- pinene, dipentene, menthol and geraniol which having anti-repellent activity. Similar findings were reported by various workers with regard to effect of plant extracts in retention of enzymatic activity of fruits during storage (Singh et al 2000).
Table 6.
Effect of pre cooling, fruit coating and packaging on the pectin content and polygalacturonase (PG) activity of Royal delicious apples during storage at 18-25 °C for 45 days
| Pectin content (% calcium pectate) | ||||||
|---|---|---|---|---|---|---|
| T | ||||||
| C1 | C2 | |||||
| P | P1 | P2 | P3 | P1 | P2 | P3 |
| T1 | 0.7 | 0.7 | 0.7 | 0.7 | 0.6 | 0.7 |
| T2 | 1.0 | 0.9 | 1.0 | 1.0 | 0.9 | 0.9 |
| T3 | 1.2 | 1.1 | 1.1 | 1.2 | 1.1 | 1.1 |
| T4 | 1.2 | 1.2 | 1.2 | 1.2 | 1.1 | 1.1 |
| T5 | 1.3 | 1.2 | 1.2 | 1.3 | 1.2 | 1.2 |
| T6 | 1.3 | 1.3 | 1.3 | 1.3 | 1.3 | 1.3 |
| T7 | 0.7 | 0.6 | 0.7 | 0.7 | 0.6 | 0.6 |
| Initial value 1.98 | ||||||
| CD0.05 C = 0.01 CxPxT = 0.03 | ||||||
| Polygalacturonase (PG) activity (% loss of viscosity) | ||||||
| T1 | 14.4 | 14.3 | 14.4 | 14.4 | 14.4 | 14.3 |
| T2 | 14.5 | 14.3 | 14.3 | 14.5 | 14.2 | 14.3 |
| T3 | 14.6 | 14.2 | 14.5 | 14.5 | 14.2 | 14.5 |
| T4 | 14.5 | 14.4 | 14.5 | 14.5 | 14.3 | 14.5 |
| T5 | 14.7 | 14.7 | 14.7 | 14.7 | 14.7 | 14.6 |
| T6 | 14.7 | 14.7 | 14.7 | 14.7 | 14.7 | 14.7 |
| T7 | 14.2 | 14.0 | 14.1 | 14.2 | 13.9 | 14.1 |
| Mean C | 14.4 | 14.4 | ||||
Initial value 10.04
CD0.05 C = 0.01, CxPxT = 0.03
T treatments; C1 pre-cooled; C2 without pre cooled; (P1) shrink wrapped tray packing; (P2) Paper mould tray + CFB carton; (P3) LDPE (150 gauge) liner + CFB carton ; marigold flower extract:T1−10%, T2−15%, T3−20% ;neem oil: T4−1%, T5−1.5%, T6−2%, T7− control. (p < 0.05), n = 3
2 % neem oil treatment (T6) was the most promising treatment to reduce fruit spoilage, as such, 1 % neem oil treatment (T4), 1.5 % neem oil treatment (T5) and 2 % neem oil treatment (T6) were statistically at par with each other. Steinhauer (1987) is isolated a compound with antifungal activity from neem kernal extracts and has been used for control of phytopathogenic fungi such as Penicillium expansum. Neem oil and its isolates nimbidin, nimbidiol, and nimbin have been reported to inhibit fungal growth (Anon 1997).The antifungal effect of neem seed kernel extracts on the postharvest disease caused by Penicillium expansum isolated from the infected fruits under in vitro condition, results showed that the growth of pathogen can be significantly (p < 0.05) reduced (Wang et al 2010). Spoilage of fruits due to rotting during storage reduced substantially by pre-cooling and coating treatments, whereas, neem oil 2 % combined with pre-cooling was found to be the most effective in reducing spoilage while control fruits exhibited maximum spoilage (Table 7). Gakhukar (1996) has given the most needed scientific explanation to the beneficial effects of plant extracts as he rightly opined that botanical extracts have the capability to act as anti-feedent and anti-repellent and, thereby, inhibiting the pathogenicity of various organisms and helped in maintaining cellular integrity and lowering the disease incidence to such an extent that the sensorial characteristics improved (Ray et al 2000).
Table 7.
Effect of pre cooling, fruit coating and packaging on the fruit spoilage (%) of Royal delicious apples during storage at 18–25 °C for 45 days
| T | ||||||
|---|---|---|---|---|---|---|
| C1 | C2 | |||||
| P | P1 | P2 | P3 | P1 | P2 | P3 |
| T1 | 3.4 | 4.5 | 3.8 | 6.0 | 5.1 | 4.4 |
| T2 | 2.6 | 3.5 | 2.7 | 4.0 | 4.7 | 4.5 |
| T3 | 1.6 | 2.7 | 2.2 | 2.6 | 3.6 | 3.2 |
| T4 | 1.2 | 1.3 | 1.4 | 1.5 | 2.3 | 1.6 |
| T5 | 0.8 | 0.7 | 0.5 | 0.8 | 0.9 | 0.9 |
| T6 | 0.7 | 0.8 | 0.7 | 0.8 | 0.9 | 0.8 |
| T7 | 5.0 | 5.4 | 5.0 | 5.9 | 6.0 | 5.5 |
CD0.05 C = 0.03, CxPxT = 0.14
T treatments; C1 pre-cooled; C2 without pre cooled; (P1) shrink wrapped tray packing; (P2) Paper mould tray + CFB carton; (P3) LDPE (150 gauge) liner + CFB carton ; marigold flower extract:T1−10%, T2−15%, T3−20% ;neem oil: T4−1%, T5−1.5%, T6−2%, T7− control. (p < 0.05), n = 3
The effect of various postharvest coating treatments on overall acceptability rating (Table 8) of apple fruits held under ambient storage conditions narrated that the average score for overall acceptability decreased during storage; and the decrease being faster in control fruits (T7) and, however, the fruits treated with 15 per cent marigold flower extract (T2) and 1.5 per cent neem oil had a maximum overall acceptability score (7.5) with shrink wrap tray packing. Similar observations were recorded by Rajkumar et al. (2006) when using wax emulsion for guava fruits.
Table 8.
Effect of pre cooling, fruit coating and packaging on the overall acceptability (rating on the basis of 9 point hedonic scale) of Royal delicious apples during storage at 18–25 °C for 45 days
| T | ||||||
|---|---|---|---|---|---|---|
| C1 | C2 | |||||
| P | P1 | P2 | P3 | P1 | P2 | P3 |
| T1 | 7.0 | 5.5 | 4.7 | 6.9 | 5.4 | 4.6 |
| T2 | 7.5 | 6.6 | 5.6 | 7.5 | 6.6 | 5.6 |
| T3 | 7.2 | 6.0 | 7.3 | 7.2 | 6.0 | 7.3 |
| T4 | 7.3 | 6.4 | 5.4 | 7.2 | 6.4 | 5.4 |
| T5 | 7.5 | 6.5 | 5.6 | 7.5 | 6.4 | 5.5 |
| T6 | 7.4 | 6.4 | 5.5 | 7.4 | 6.4 | 5.5 |
| T7 | 4.7 | 4.3 | 4.3 | 4.6 | 4.3 | 4.3 |
CD0.05 C = 0.01, CxPxT = 0.14
T treatments; C1 pre-cooled; C2 without pre cooled; (P1)-shrink wrapped tray packing; (P2) Paper mould tray + CFB carton; (P3) LDPE (150 gauge) liner + CFB carton ; marigold flower extract:T1−10%, T2−15%, T3−20% ;neem oil: T4−1%, T5−1.5%, T6−2%, T7− control. (p < 0.05), n = 3
Conclusions
The results revealed that 1.5–2% concentration of neem oil as a surface coating along with pre-cooling at 10 °C was the most effective in providing better physico-chemical umbrella, significantly lowering the fruit spoilage. The neem oil surface coating along with shrink wrap tray packing under 18–25 °C (65–75% RH) resulted the longest storage life up to 45 days. Among three different concentrations of marigold flower extracts (10%, 15%, 20% ), higher retention of fruit firmness, pectin content, anthocyanin pigments, PG enzyme activity was recorded by 20% marigold extract surface coating with shrink wrap tray packing along with pre cooling. Future research should be needed to encourage the use of such botanicals for development of edible wax formulations for other economically important fruits and to popularize among farmers.
Acknowledgement
Author acknowledge Sri Lankan Council for Agricultural Research Policy, Institute of Post-harvest Technology and ICAR-CARP work plan to organize and sponsor study at Dr Y S Pamar University of Horticulture and Forestry, Nauni, Solan.
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