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Increasing protein demands directly require additional resources to those presently and recurrently available. Emerging green technologies have witnessed an escalating interest in "Cavitation Processing" (CP) to ensure a non-invasive, non-ionizing and non-polluting extraction. The main intent of this review is to present an integrated summary of cavitation extraction methods specifically applied to food protein sources. Along with a comparative assessment carried out for each type of cavitation model, protein extraction yield and implications on the extracted protein's structural and functional properties. The basic principle of cavitation is due to the pressure shift in the liquid flow within milliseconds. Hence, cavitation emerges similar to boiling; however, unlike boiling (temperature change), cavitation occurs due to pressure change. Characterization and classification of sample type is also a prime candidate when considering the applications of cavitation models in food processing. Generally, acoustic and hydrodynamic cavitation is applied in food applications including extraction, brewing, microbial cell disruption, dairy processing, emulsification, fermentation, waste processing, crystallisation, mass transfer and production of bioactive peptides. Micro structural studies indicate that shear stress causes disintegration of hydrogen bonds and Van der Waals interactions result in the unfolding of the protein's secondary and/or tertiary structures. A change in the structure is not targeted but rather holistic and affects the physicochemical, functional, and nutritional properties. Cavitation assisted extraction of protein is typically studied at a laboratory scale. This highlights limitations against the application at an industrial scale to obtain potential commercial gains.

Application of non-thermal treatment to proteins prior to enzymatic hydrolysis can facilitate the release of novel bioactive peptides (BPs) with unique biological activities. In this study, lupin protein isolate was pre-treated with ultrasound and hydrolysed using alcalase and flavourzyme to produce alcalase hydrolysate (ACT) and flavourzyme hydrolysate(FCT). These hydrolysates were fractionated into 1, 5, and 10 kDa molecular weight fractions using a membrane ultrafiltration technique. The in vitro angiotensin-converting enzyme (ACE) studies revealed that unfractionated ACT (IC

The present study was designed to study the effect of green solvent processing in two folds, (i) to extract valuable protein from dairy and non-dairy expired milk products and (ii) to compare extraction efficiency and quality of extracted protein using conventional (CS) and green solvents (GS). Ethyl acetate, ethanol, isopropanol, n-heptane and cyclopentyl methyl ether (CPME) were selected as the GS for the possible substitution of hexane and ethyl ether. For each respective solvent, protein recovery, structural and functional modifications were studied. Protein yield was extracted most effectively by GS n-heptane in dairy milk (5.33 ± 0.01%) with a protein purity of 39.73 ± 0.90%. Non-dairy milk and product had similar protein yield when treated with CS and GS. Total mean of extraction efficiency, structural and functional modifications across all samples showed GS solvents were statistically more effective than CS.

Ultrasound treatment at different power output (0, 25 and 29W) and exposure time (10 and 15min) was used to investigate its effect on the phenolic metabolism enzymes, total phenolic content and antioxidant capacity of fresh-cut pineapple. Following ultrasound treatment at 25 and 29W, the activity of phenylalanine ammonia lyase (PAL) was increased significantly (P0.05) by 2.0 and 1.9-fold, when compared to control. Meanwhile, both the activity of polyphenol oxidase (PPO) and polyphenol peroxidase (POD) in fresh-cut pineapple was significantly (P0.05) lower than control upon subjected to ultrasound treatment. In the present study, induction of PAL was found to significantly (P0.001) correlate with higher total phenolic content and thus higher antioxidant capacity in fresh-cut pineapple. Results suggest that hormetic dosage of ultrasound treatment can enhance the activity of PAL and total phenolic content and hence the total antioxidant capacity to encounter with oxidative stress.

The physicochemical properties of drum dried pregelatinized (PG) and granular cold-water-swelling (GCWS) corn starch pastes were determined in the presence of NaCl and CaCl2 (0, 50, 100, 150 and 200mM). Light micrographs revealed that NaCl roughened the surface of PG starch particles while CaCl2 did not bring about obvious changes on their morphology. In the case of GCWS starch, there were some wrinkles on the surface of starch granules. NaCl increased the wrinkles but CaCl2 softened the surface of granules. GCWS starch had higher water absorption, cold paste viscosity and textural parameters than PG starch and these parameters were enhanced with addition of CaCl2 while NaCl exhibited an opposite trend for all of these factors. The Freeze-thaw (F-T) stability and turbidity of GCWS were also higher than PG starch. In presence of salts F-T stability and turbidity of both modified starches improved and CaCl2 caused more evident changes.

Pregelatinized starches are physically modified starches with ability to absorb water and increase viscosity at ambient temperature. The main purpose of this study was to determine how different concentrations of acetic acid (0, 500, 1000, 10,000 mg/kg) can affect functional properties of pregelatinized wheat and corn starches (PGWS and PGCS, respectively) produced by a twin drum drier. With increasing acetic acid following changes occurred for both samples; cold water solubility (at 25 °C) increased, water absorption and apparent cold water viscosity (at 25 °C) reduced, the smooth surface of the starch particles converted to an uneven surface as confirmed by scanning electron microscopy, cohesiveness, consistency and turbidity of the starch gels reduced while their syneresis increased. It was found that in presence of acetic acid, PGWS resulted in higher water absorption and apparent cold water viscosity and produced more cohesive and turbid gels with less syneresis compared to PGCS.

A major drawback to the extension of NaOH-free olive debittering is its lengthy processing. In this research, the power ultrasound efficacy was investigated in a laboratory scale to accelerate this process. Olive fruits were sonicated in water or brine (15% NaCl). The effects of ultrasound-assisted debittering (UAD) were evaluated on olives physicochemical and textural properties in comparison with conventional debittering (CD). In UAD, however, the removal rate of phenolic compounds, which cause olives natural bitterness, increased significantly and as a result, the processing time decreased by 37.8% and 38.6% when debittering was done in water and brine, respectively. The chemical compositions, fatty acids profile, total color differences, Firmness and other textural parameters of UAD-treated samples remained unchanged and their antioxidant activity was significantly higher in comparison with CD-treated samples. Remarkably, UAD was able to speed up and promote NaOH-free olive debittering, without causing any undesirable changes.

The influence of κ-carrageenan (KC) depolymerization using ultrasound on its interaction with β-lactoglobulin (BLG) was investigated by isothermal titration calorimetry (ITC), turbidity measurement, dynamic light scattering and zeta-potential analyses. Time and amplitude of the sonication had a direct effect on the viscosity depression, while the sonication temperature had an opposite effect. ITC measurements indicated that the sonication significantly decreased the affinity constant between KC and BLG. The zeta-potential of the nanoparticles produced from ultrasonicated (US) KC–BLG associative interaction was lower than of those produced from intact (IN) KC–BLG interaction. These differences were attributed to the lower charge density of the KC (US) as a result of sonochemical interactions. Polydispersity and particle size measurements showed that the effect of the sonication was the homogenisation of the nanoparticles in the mixed dispersion. The nanoparticles formed may therefore be useful as a delivery system for fortification purposes of acidic beverages.

Applications of glutenin and gliadin in food products are limited as they cannot provide desirable functional properties. The objectives of this study were to improve the functional properties of glutenin and gliadin by acetylation using acetic anhydride and to study these properties at pH 3, 6 and 9. Under the experimental conditions, about 53.88% of glutenin and 28.46% of gliadin were acetylated. pH of the medium and acetylation of the proteins affected water solubility, water absorption, water holding capacity, emulsifying and foaming properties of the samples. The results of the sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that high and low molecular weight glutenin subunits and ω-gliadins were affected by acetylation, while pH changes had no significant effect on the molecular weight of the proteins. Taken together, the results showed that acetylated glutenin and gliadin can be used as protein sources with good functional properties, particularly at alkaline pH.

In this study the effects of L-Cysteine as a food additive on wheat starch characteristics before and after gelatinization were studied. L-Cysteine (63 mg/kg, starch basis) was added to slurry of wheat starch in water (30%, w/w). One set of samples was prepared by mixing it at 40 °C for 45 min. Another set was gelatinized at 100 °C for 45 min. The scanning electro-micrographs of the samples prepared at 40 °C in the presence of L-Cysteine showed some spots on the granules. However, thermal properties, X-ray patterns and the degree of crystallinity of the samples did not obviously change (P > 0.05); while a reduction in intrinsic viscosity, peak and final viscosities of the samples was observed. After gelatinization, intrinsic, peak and final viscosities of the samples were reduced. Some of these changes may indicate degradation of starch molecules in the presence of L-Cysteine, particularly after gelatinization.

The effect of chitosan on the physicochemical characteristics of Eksotika II papaya fruit stored at 12 ± 1 °C and 85–90% relative humidity, was investigated. Chitosan provided an effective control in reducing weight loss, maintained firmness, delayed changes in the peel colour and soluble solids concentration during 5 weeks of storage. The titratable acidity declined throughout the storage period, though at a slower rate in the chitosan coated fruit as compared to the control. Sensory evaluation results also confirmed the efficacy of chitosan. Consequently, the internal gaseous concentrations of CO2 and O2 also proved the usefulness of chitosan. These findings suggest that chitosan can be used commercially for prolonging the storage life of Eksotika II papaya fruit.

Softening-associated changes in a cold-water-soluble pectin, CWP3 of Japanese persimmon fruit are investigated by methylation analysis. Methylation analysis showed that rhamnose occurred as (1 → 2)- and (1 → 2,4)-linked residues in CWP3 (from fresh persimmon), newly solubilized CWP3 (fraction ‘a’ from sun-dried persimmon) and depolymerized CWP3 (fraction ‘b’ from sun-dried persimmon) as expected for the presence of ‘hairy’ regions. Solubilization of pectin into CWP3 occurred with higher proportions of (1 → 5)-linked arabinan side-chains and lower proportions of (1 → 3)/(1 → 6)-linked arabinogalactan side-chains compared to the respective side chains in CWP3 (fresh persimmon). During the sun-drying process, marked losses of (1 → 3,6)-linked galactose residues from CWP3 occurred, due to extensive degradation of main-chains of arabinogalactans. This implied losses of both types of sugars, arabinose (as terminal) and galactose from arabinogalactans in CWP3 of Japanese persimmon. During the sun-drying process, the molecular size distribution of CWP3 was affected due to degradation of arabinogalactan and arabinan side-chains.

Cold-water-soluble pectic polysaccharides (CWPs) from fresh and sun-dried Japanese persimmon (Diospyros kaki) were fractionated through DEAE-cellulose (phosphate form) column and in both cases, CWPs were separated into five fractions, CWP1, CWP2, CWP3, CWP4 and CWP5. Each CWP3 was subjected to gel filtration chromatography on a Sepharose CL-6B column. Gel filtration showed that solubilization of pectin as high-molecular-weight polymer into CWP3 and depolymerization of CWP3 occurred during the sun-drying process. CWP3 (fresh persimmon) contained galactose as the predominant neutral sugar, whereas arabinose was the predominant neutral sugar in newly solubilized CWP3. A low-molecular-weight fraction of CWP3 (sun-dried persimmon) represented mainly the rhamnogalacturonan backbone of ‘hairy’ regions. The molecular size distribution of CWP3 was affected due to degradation of side-chains. Loss of arabinose occurred at a slower rate than galactose from CWP3. The results imply a softening-associated modification of Japanese persimmon pectin during the sun-drying process.

The objective of this study was to compare the physico-chemical characteristics and antioxidant activity of ozone-treated papaya fruit and untreated fruit. Freshly harvested papaya fruit were exposed continuously to ozone fumigation (0, 1.5, 2.5, 3.5 and 5 ppm) for 96 h prior to ambient storage at 25 ± 3 °C and 70 ± 5% relative humidity (RH) for up to 14 days. The fruit exposed to 2.5 ppm ozone had higher levels of total soluble solids (25.0%), ascorbic acid content (12.4%), β-carotene content (19.6%), lycopene content (52.1%), and antioxidant activity (30.9%), and also reduced weight loss (11.5%) at day 10 compared to the control. The sensory attributes of papaya treated with 2.5 ppm ozone was superior in sweetness and overall acceptability. These results support the application of ozone as a non-thermal and safe food preservation technique for papaya which can benefit both the producers and consumers.