Table 3.

Ultrasound technologies for efficiency improvements in the food industry

Type of ultrasound technology	Features	Sample	Frequency (kHz)	Time (min)	Power (W)	Temperature (°C)	Conclusion	References
Ultrasonication	Low temperature used for isolation of enzymes Proven to improve efficiency of proteins and functional foods Applicable for heat sensible products Recently used in wine fermentation to decrease the ageing time	Spices of tangerine peels, parsley, red pepper	–	30	–	40	Tangerine peels: special fragrance due to limonene and citral flavor substance Parsley: slight bitterness due to phenolic ether Red pepper: slightly sweet and spicy due to capsaicin and radish	Teng et al. (2019)
		Quince fruit	28	15	50	–	Yeast growth inhibition observed Low enzymatic activity and browning Lowest off odor obtained when treated with ultrasound	Yildiz et al. (2020)
Manosonication	Involves a combination of ultrasound and pressure applied together Inactivates enzymes at low temperature and moderate pressures Efficiency higher than ultrasonication Effective in maintaining taste, nutrient qualities and sensorial attributes in liquid foods, fruits, vegetables and recently in nanofoods	Apple, cranberry and blueberry juice	20	3,6,9	–	20,40,60	Complete inactivation of bacteria at 60 °C in 6 and 9 min. No change observed in 20 °C, 40 °C Change of 3.5–5.9 log units observed as per the conventional treatment	Režek Jambrak et al. (2018)
		Citrus waste	40% amplitude, 250 kPa	20	–	42	Analysis using Box-Behnken design Highest extractability of pectin: 27.83% Ultrasound: 22.83% Heat: 24.71%	Hu et al. (2020)
Thermosonication	Involves a combination of ultrasound and heat applied together Used for sterilization or pasteurization purposes Better to use as compared to any other thermal treatment due to its high precision Found to improve the physicochemical and sensorial characteristics of fruits, beer, dairy, rice and mixed juices	Orange juice		12 days		4	Bioactive compounds decreased during storage, while pectin methyl esterase values increased Changes observed from the 12th day of storage. Storage at 4 °C proved increase in shelf life	Wahia et al. (2020)
		Milk	–	4	–	60	Central composite rotatable design used for determining the effect 53.7 °C and 52 °C showed removal of pathogens from milk Combination of pasteurization and thermosonication (11.1 s) increase shelf life by 2 weeks Retinol levels remained stable after processing	Deshpande and Walsh (2020); Parreiras et al. (2020)
		Red pitaya juice	–	1.5	–	83	Degradation and isomerism of betanin and phyllocactin More than 92.97% retention of polyphenols in the juice	Liao et al. (2020)
		Mung bean protein	20	5, 10, 20, 30		30, 50, 70	Particle size reduction and free sulfhydryl content with time Increase of hydrophobicity and exposure of non-polar groups Twofold increase in protein solubility, clarity at 70 °C No change observed at 30 °C and 50 °C	Zhong and Xiong (2020)
Manothermosonication	Involves a combination of heat, ultrasound and pressure Isolation of enzymes or bioactive compounds at a shorter time interval Maximum cavitation as compared to other types Generally used for isolation of lipids and proteins Recently used for improving shelf life and food safety in citrus foods and dairy products	Wine	24	–	400	30, 40	Significant reduction of brettanomyces (89.1–99.7%) and lactic acid bacteria (71.8–99.3%) Results indicate great potential for treatment in continuous flow system for decreasing preservatives	Gracin et al. (2016)
		Modified pectin	400	5	–	45	Lower activation energy observed during kinetics Lowered degree of methoxylation and galacturonic acid Higher antioxidant activity as compared to citrus pectin	Wang et al. (2020a)
		Ferritin	200 kPa	40 s	–	50	Reduced content of alpha helix structure. Steady maintenance of spherical morphology (12 nm) Increase in iron release activity pH changes observed and tested in encapsulation of tea polyphenol epigallocatechin Increase in water solubility and encapsulation efficiency	Meng et al. (2019)