Effect of pulsed ultrasound, a green food processing technique, on the secondary structure and in-vitro digestibility of almond milk protein

Fabrication and characterization of double-network meat analogs based on camellia oleosomes and soy protein-wheat gluten induced by transglutaminase and calcium alginate

Plant-based meat analogs often exhibit poor elasticity, limited water-holding capacity, and lack a well-integrated fat-phase, which limits their applications in food industry. This study aimed to introduce camellia seed-derived oleosomes as templates for lipid droplets into textured soy protein-wheat gluten, followed by dual-crosslinking using transglutaminase (TG) and sodium alginate with varying Ca2+ concentrations. Results showed that oleosomes inclusion transformed the porous structures of textured proteins into droplet-embedded protein matrices, along with enhanced hardness, increased lightness, and reduced redness. TG induction promoted the ε-(γ-glutamyl)-lysine bonds between oleosomes and continuous-phase proteins, while sodium alginate, reinforced by Ca2+, created a robust network structure with smaller pore sizes and more interaction zones that tightly held the oleosomes. The addition of 10-20 mM CaCl2 significantly increased the immobilized water content, G' values and promoted the transformation of β-turns to β-sheets. According to Lissajous-Bowditch analyses, oleosome-protein meat analog was identified as a soft gel, exhibiting erratic and abrupt changes at strain ≤10 %. In contrast, TG-treated analogs, particularly those with both TG and Ca2+, exhibited greater structural elasticity and resistance to large deformations (≤500 %), due to double-network structures with enhanced mechanical strength and reversible deformation resistance. Additionally, double-crosslinked meat analogs significantly influenced the rate of lipid digestion.

A review on apricot kernel seed proteins and peptides: Biological functions and food applications

Apricot kernel seed proteins, containing over 60 % protein, have gained attention as a potential solution to the global protein shortage and sustainable use of agricultural by-products. While research has primarily focused on their content, composition, and structural properties, there remains a lack of comprehensive studies on the extraction methods and the preparation of bioactive peptides. This review highlights the nutritional value of apricot kernel seed proteins, explores strategies to reduce allergenicity, and examines their bioactive peptide functions. It also discusses the potential applications of these proteins in food technology and pharmaceuticals, emphasizing their versatility. The valorization of apricot kernel seed proteins could help address protein scarcity, but challenges persist, including optimizing extraction techniques, mitigating allergenicity, and developing bioactive peptides with diverse physiological effects. Future research should focus on enhancing protein extraction, reducing allergenicity, and advancing the mass production of functional foods and therapeutic agents from apricot kernel seed proteins. Interdisciplinary efforts are essential to fully unlock their potential and contribute to sustainable development.

Ultrasound-treated hybrid protein gels from pea and whey: A comparison of gastric breakdown mechanisms with commercial protein-based foods

A novel hybrid protein gel was developed to sustainably meet the growing demands for protein with pea and whey protein isolates (3:2 in 15 % w/v protein content) which was ultrasound treated (7.5 and 15 min), and gelled (90 °C, 60 min). The study investigated the impact of ultrasound treatment on the structure and gastric breakdown kinetics of hybrid protein gels and compared these properties to commercial protein-based foods (ham, paneer, and mozzarella). Ultrasound treatment for 15 min significantly (p < 0.05) reduced particle size (d50: 5.4 µm vs 32.5 µm in control) and resulted in a higher initial Young's modulus than control. Protein hydrolysis at 180 min was ∼53 % lower (p < 0.05) with 15 min ultrasound treatment than control and 7.5 min ultrasound treatment. Hybrid protein gels exhibited similarities in initial Young's modulus to mozzarella (p > 0.05), while ham and paneer were significantly firmer (p < 0.05). Effective diffusivity of moisture from gastric fluid decreased (p < 0.05) in the order: ham > paneer and mozzarella > hybrid protein gels. In contrast, the effective acid diffusivity from gastric fluid was similar (p > 0.05) between hybrid protein gels and paneer, which were ∼74 % higher (p < 0.05) than ham and mozzarella. Digestion time influenced (p < 0.05) breakdown mechanisms (texture, dry matter loss, moisture, and acid uptake) during digestion. This study confirmed that hybrid protein gels were comparable to commercial protein-based foods and the limiting factor driving gastric breakdown is unique to different foods incorporating proteins.

Structural changes and in vitro bioaccessibility of CPP-febisgly complexes: Dependence on iron load

The effect of casein phosphopeptides (CPP) and ferrous bisglycinate (FebisGly) at different ratios (1:20, 1:10, and 1:5 w/w) on iron supplementation was investigated. The in vitro bioaccessibility, structural changes, antioxidant activity, and the effect of absorption inhibitors were also explored. The results demonstrated that CPP enhanced the bioaccessibility of FebisGly by 68.72 % ± 0.18 % and increased the β-sheet content from 21.60 % ± 0.23 % to 67.92 % ± 0.12 %, forming a stable secondary structure. The particle size distribution (PSD) and rheological analyses indicated that CPP significantly contributed to the formation of chelated irons, resulting in a uniform PSD and enhanced viscoelasticity. Moreover, it prolonged the gastric emptying time, reducing gastric irritation further. The carboxyl and amino groups in the CPP molecules participated in chelation reaction, improved the antioxidant activity, and competed with phytic acid, tannic acid, and cellulose for iron. Overall, these results laid a foundation for developing novel iron supplementation strategies.

Nutritional health aspects and functional properties of nut yogurt: Future perspectives

The increase in lactose intolerance, the rise of veganism, the pursuit of healthy lifestyles, environmental awareness and concern for animal welfare have led to an increase in consumer demand for plant-based yogurts. The high nutritional value of nuts makes them an ideal ingredient for the production of plant-based yogurts. The main challenge for such products is to achieve a similar taste to traditional yogurt while improving shelf life. In recent years, extensive research has been conducted on this topic. The nutritional and health properties of yogurts made from different types of nuts, traditional and innovative processing technologies, and the effects of fermentation on the nutritional value, sensory characteristics, and texture of the yogurts are described. This review provides a comprehensive overview of the nutritional and manufacturing process of nut yogurts and offers possible directions for development and innovation of health food products.

Alaska pollock surimi-based meat analogs by high-moisture extrusion: Effect of konjac glucomannan/curdlan/carrageenan/sodium alginate on fibrous structure formation

This study investigated the effects of the addition of konjac glucomannan (KGM), curdlan (CD), carrageenan (CA), and sodium alginate (SA) on fibrous structure formation in surimi-based meat analogs to livestock meat. Meat analogs were prepared using high-moisture extrusion with Alaskan pollock surimi and soy protein isolate at a ratio of 7:3 (w/w). The meat analogs samples were labeled as SSP. Macrostructure observation showed that the best fibrous structure was obtained in SSP containing 2% SA. Mesostructure and microstructure observations revealed that 2% CD, CA or SA promoted the formation of a less tight three-dimensional network structure, which contributed to the formation of fiber filaments. Increased β-sheet structure content, ordered degree, fractal dimension and thermal stability were observed in SSP with the three colloids. Moreover, fibrous texture was closely associated with the thermal stability and fractal dimension. This study has provided useful information for colloid application in surimi-based meat analogs.

Enhancing the Stability of Litsea Cubeba Essential Oil Emulsions Through Glycosylation of Fish Skin Gelatin via Dry Maillard Reaction

Emulsions are widely utilized in food systems but often face stability challenges due to environmental stresses, such as pH, ionic strength, and temperature fluctuations. Fish skin gelatin (FSG), a promising natural emulsifier, suffers from limited functional properties, restricting its broader application. This study explored the enhancement of emulsion stability in Litsea cubeba essential oil systems through the glycosylation of fish skin gelatin (FSG) with dextran via the dry Maillard reaction. Among dextrans of varying molecular weights (10 kDa, 100 kDa, 200 kDa, and 500 kDa), the 200 kDa dextran exhibited the best emulsification performance, achieving a remarkable 160.49% increase in stability index. The degree of grafting (DG) increased with molecular weight, peaking at 34.77% for the 500 kDa dextran, followed by 23.70% for the 200 kDa variant. The particle size of the FSG-Dex 200 kDa conjugate emulsion was reduced to 639.1 nm, compared to 1009-1146 nm for the unmodified FSG, while hydrophobicity improved by 100.56%. The zeta potential values approached 30 mV, indicating enhanced stability. Furthermore, glycosylation significantly improved antioxidant activity, as evidenced by increased radical scavenging capacity in both DPPH and ABTS assays. These findings underscore the potential of glycosylated FSG as a natural emulsifier in food applications.

Enhancing vitamin D3 bioaccessibility: Unveiling hydrophobic interactions in soybean protein isolate and vitamin D3 binding via an infant in vitro digestion model

In the domain of infant nutrition, optimizing the absorption of crucial nutrients such as vitamin D3 (VD3) is paramount. This study harnessed dynamic-high-pressure microfluidization (DHPM) on soybean protein isolate (SPI) to engineer SPI-VD3 nanoparticles for fortifying yogurt. Characterized by notable binding affinity (Ka = 0.166 × 105 L·mol-1) at 80 MPa and significant surface hydrophobicity (H0 = 3494), these nanoparticles demonstrated promising attributes through molecular simulations. During simulated infant digestion, the 80 MPa DHPM-treated nanoparticles showcased an impressive 74.4% VD3 bioaccessibility, delineating the pivotal roles of hydrophobicity, bioaccessibility, and micellization dynamics. Noteworthy was their traversal through the gastrointestinal tract, illuminating bile salts' crucial function in facilitating VD3 re-encapsulation, thereby mitigating crystallization and augmenting absorption. Moreover, DHPM treatment imparted enhancements in nanoparticle integrity and hydrophobic properties, consequently amplifying VD3 bioavailability. This investigation underscores the potential of SPI-VD3 nanoparticles in bolstering VD3 absorption, thereby furnishing invaluable insights for tailored infant nutrition formulations.

Impact of thermal ultrasound on enzyme inactivation and flavor improvement of sea cucumber hydrolysates

In this study, the effects of the thermal ultrasonic enzyme inactivation process on flavor enhancement in sea cucumber hydrolysates (SCHs) and its impact on the inactivation of neutral proteases (NPs) were investigated. The body wall of the sea cucumber was enzymatically hydrolyzed with NPs. On the one hand, the structure of NPs subjected to different enzyme inactivation methods was analyzed using ζ-potential, particle size, and Fourier transform infrared (FT-IR) spectroscopy. On the other hand, the microstructure and flavor changes of SCHs were examined through scanning electron microscopy, E-nose, and gas chromatography-ion mobility spectrometry (GC-IMS). The results indicated that thermal ultrasound treatment at 60 °C could greatly affect the structure of NPs, thereby achieving enzyme inactivation. Furthermore, this treatment generated more pleasant flavor compounds, such as pentanal and (E)-2-nonenal. Hence, thermal ultrasound treatment could serve as an alternative process to traditional heat inactivation of enzymes for improving the flavor of SCHs.

Modification of soy protein isolate and pea protein isolate by high voltage dielectric barrier discharge (DBD) atmospheric cold plasma: Comparative study on structural, rheological and techno-functional characteristics

The modification in structural, rheological, and techno-functional characteristics of soy and pea protein isolates (SPI and PPI) due to dielectric barrier discharge cold plasma (DBD-CP) were assessed. The increased carbonyl groups in both samples with cold plasma (CP) treatment led to a reduction in free sulfhydryl groups. Moreover, protein solubility of treated proteins exhibited significant improvements, reaching up to 59.07 % and 41.4 % for SPI and PPI, respectively, at 30 kV for 8 min. Rheological analyses indicated that storage modulus (G') was greater than loss modulus (G″) for CP-treated protein gels. Furthermore, in vitro protein digestibility of SPI exhibited a remarkable improvement (4.78 %) at 30 kV for 6 min compared to PPI (3.23 %). Spectroscopic analyses, including circular dichroism and Fourier Transform-Raman, indicated partial breakdown and loss of α-helix structure in both samples, leading to the aggregation of proteins. Thus, DBD-CP induces reactive oxygen species-mediated oxidation, modifying the secondary and tertiary structures of samples.

Extrusion puffing as a pretreatment method to change the surface structure, physicochemical properties and in vitro protein digestibility of distillers dried grains with solubles

BACKGROUND

Distillers dried grains with solubles (DDGS) are rich in nutrition, and they are potential protein feed raw material. However, the existence of cellulose, hemicellulose and lignin hinders animals' digestion and absorption of DDGS. Making full use of unconventional feed resources such as DDGS can alleviate the shortage of feed resources to a certain extent. This research investigated the effects of twin-screw extrusion on the macromolecular composition, physical and chemical properties, surface structure and in vitro protein digestibility (IVPD) of DDGS.

RESULTS

The findings showed that extrusion puffing significantly increased the protein solubility, bulk density, water holding capacity, and swelling capacity, while significantly decreased hemicellulose and crude protein content, particle size and zeta potential of DDGS. The structure damage of DDGS induced by the extrusion was characterized by scanning electron microscopy (SEM), Fourier-transform infrared (FITR) spectroscopy and X-ray diffraction (XRD) analysis. Interestingly, no random coil was observed in the analysis of the secondary structure, and extrusion promoted the transformation of α-helix and β-turn to β-sheet, which led to significant increases in protein solubility and IVPD of DDGS (P < 0.05). Additionally, correlation analysis revealed that IVPD and PS had a positive relationship.

CONCLUSION

Extrusion puffing was an ideal pretreatment method for DDGS modification to improve in vitro protein digestibility. © 2023 Society of Chemical Industry.

Influence of heat treatment before and/or after high-pressure homogenization on the structure and emulsification properties of soybean protein isolate

This study investigates the effects of heat treatment before high-pressure homogenization (HHPH) and heat treatment after high-pressure homogenization (HPHH) at different pressures (20, 60, and 100 MPa) on the structural and emulsification properties of soy protein isolate (SPI). The results indicate that HHPH treatment increases the surface hydrophobicity (H0) of the SPI, reduces β-fold and irregular curls, leading to the formation of soluble aggregates, increased adsorbed protein content, and subsequent improvements in emulsification activity index (EAI) and emulsion stability index (ESI). In contrast, the HPHH treatment promoted the exchange of SH/SS bonds between protein molecules and facilitated the interaction of basic peptides and β-subunits, leading to larger particle sizes of the soluble aggregates compared to the HHPH-treated samples. However, excessive aggregation in HPHH-treated aggregates leads to decreased H0 and adsorbed protein content, and increased interfacial tension, negatively affecting the emulsification properties. Compared to the HPHH treatment, HHPH treatment at homogenization pressures of 20 to 100 MPa increases EAI and ESI by 5.81-29.6 % and 5.31-25.9 %, respectively. These findings provide a fundamental basis for soybean protein manufacturers to employ appropriate processing procedures aimed at improving emulsification properties.

Yeast protein as a novel dietary protein source: Comparison with four common plant proteins in physicochemical properties

Currently, with the preference for a healthy diet and increased awareness of reducing the carbon footprint, the demand for protein is becoming more and more diversified. In this study, the physicochemical properties of yeast protein (YP) and four common plant proteins (soy protein isolate, pea protein isolate, wheat gluten, and peanut protein) were compared. The most prevalent secondary structure in YP is the β-sheet. Furthermore, YP is in an aggregated state, and it has a high surface hydrophobicity. The tryptophan residues are primarily exposed on the polar surface of YP. The results of in vitro digestibility indicated that YP (84.91 ± 0.52%) was a high-quality protein. Moreover, YP has a higher thermal stability and relatively stable low apparent viscosity, which provides ample possibility for its application in food processing and in foods for people with swallowing difficulties. This study provides theoretical basis in the potential of YP as an alternative protein source.

Effect of high intensity ultrasonic treatment on structural, rheological, and gelling properties of potato protein isolate and its co-gelation properties with egg white protein

The study aimed to investigate the effect of high intensity ultrasonic (HIU) treatment at different times (0, 10, 20, and 30 min) on the structure and gel properties of water-soluble potato protein isolate (WPPI) and to further investigate the improvement of gel properties of ultrasonicated WPPI (UWPPI) by the addition of egg white protein (EWP). HIU reduced the particle size of WPPI, whose structure became loose and disordered, which improved gelling properties of UWPPI. Fourier transform infrared results indicated that α-helix content decreased, whereas the proportion of irregular curl increased with the increase in ultrasonication time (0-20 min), indicating that the initially ordered structure of UWPPI became disordered. After HIU treatment, the free sulfhydryl groups of UWPPI and surface hydrophobicity decreased and fluorescence intensity increased. These results demonstrated that the HIU loosened the structure of UWPPI, exposing more chromogenic groups while embedding more hydrophilic groups. After thermal induction, UWPPI gel hardness increased and exhibited excellent water holding capacity. After the addition of EWP, rheological properties stabilized, and the hardness of UWPPI-EWP gels increased significantly, forming internally structured protein gels with a tightly ordered structure and increased brightness. Thus, HIU changed the structure and gelling properties of WPPI, and the addition of EWP further enhanced the performance of hybrid protein gels. PRACTICAL APPLICATION: High intensity ultrasonic changed the structure of water-soluble potato protein isolate (WPPI) and improved the properties of WPPI gels. The addition of egg white protein significantly improved the quality of mixed protein gels which showed great potential industrial value.

Evaluating the influence of cold plasma bubbling on protein structure and allergenicity in sesame milk

BACKGROUND

Sesame is a traditional oilseed comprising essential amino acids. However, the presence of allergens in sesame is a significant problem in its consumption; thus, this study attempted to reduce these allergens in sesame oilseeds.

OBJECTIVE

The present study aimed to evaluate the effect of cold plasma processing on structural changes in proteins, and thereby the alteration of allergenicity in sesame milk. Method: Sesame milk (300 mL) was processed using atmospheric pressure plasma bubbling unit (dielectric barrier discharge, power: 200 V, and airflow rate: 16.6 mL/min) at different exposure times (10, 20, and 30 min).

RESULTS

The efficiency of plasma-bubbling unit as measured by electron paramagnetic resonance in terms of producing reactive hydroxyl (OH) radicals proved that generation of reactive species increased with exposure time. Further, the plasma-processed sesame milk subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and differential scanning calorimetery analysis revealed that plasma bubbling increased the oxidation of proteins with respect to bubbling time. The structural analysis by Fourier transform infrared spectroscopy and circular dichroism revealed that the secondary structure of proteins was altered after plasma application. This change in the protein structure helped in changing the immunoglobulin E (IgE)-binding epitopes of the protein, which in turn reduced the allergen-binding capacity by 23% at 20-min plasma bubbling as determined by the sandwich-type enzyme-linked immunosorbent assay. However, 30-min plasma bubbling intended to increase allergenicity, possibly because of increase in IgE binding due to the generation of neo epitopes.

CONCLUSION

These changes proved that plasma bubbling is a promising technology in oxidizing protein structure, and thereby reducing the allergenicity of sesame milk. However, increase in binding at 30-min bubbling is to be studied to facilitate further reduction of the binding capacity of IgE antibodies.

Evaluation of key aroma compounds and protein secondary structure in the roasted Tan mutton during the traditional charcoal process

The traditional charcoal technique was used to determine the changes in the key aroma compounds of Tan mutton during the roasting process. The results showed that the samples at the different roasting time were distinguished using GC-MS in combination with PLS-DA. A total of 26 volatile compounds were identified, among which 14 compounds, including (E)-2-octenal, 1-heptanol, hexanal, 1-hexanol, heptanal, 1-octen-3-ol, 1-pentanol, (E)-2-nonenal, octanal, 2-undecenal, nonanal, pentanal, 2-pentylfuran and 2-methypyrazine, were confirmed as key aroma compounds through the odor activity values (OAV) and aroma recombination experiments. The OAV and contribution rate of the 14 key aroma compounds were maintained at high levels, and nonanal had the highest OAV (322.34) and contribution rate (27.74%) in the samples after roasting for 10 min. The content of α-helix significantly decreased (P < 0.05), while the β-sheet content significantly increased (P < 0.05) during the roasting process. The content of random coils significantly increased in the samples roasted for 0-8 min (P < 0.05), and then no obvious change was observed. At the same time, β-turn content had no obvious change. Correlation analysis showed that the 14 key aroma compounds were all positively correlated with the content of α-helix and negatively correlated with the contents of β-sheet and random coil, and also positively correlated with the content of β-turn, except hexanal and 2-methypyrazine. The results are helpful to promoting the industrialization of roasted Tan mutton.

Recent advances on the impact of novel non-thermal technologies on structure and functionality of plant proteins: A comprehensive review

The recent trend in consumption of plant-based protein over animal protein opens up a new avenue for sustainable agriculture practice, less environmental impact and greenhouse gas emission. The modification of plant-based proteins by novel non-thermal technologies includes the structural transformation followed by the modulation of their functional properties that are exploited to develop a protein ingredient system for application in food formulation. This review explores the impact of non-thermal process technologies on structural modification of plant proteins followed by improvement in protein's function in food formulation. Novel concepts articulating the impact of non-thermal technologies on structural and functional modification of plant proteins affecting it's digestibility and bioavailability are addressed. Limitations and prospects of applying non-thermal technologies in developing an alternative plant-based protein food system are also summarized. Non-thermal processes are considered as the emerging technologies that results in conformational changes in secondary, tertiary and quaternary structure of plant proteins which helps in modification of functional properties without jeopardizing the organoleptic properties and bioactivity of the protein. However, extensive future study is needed to optimize the non-thermal process parameters along with the finding of new protein sources to achieve healthy and sustainable plant-based food system.

Legume Seed Protein Digestibility as Influenced by Traditional and Emerging Physical Processing Technologies

The increased consumption of legume seeds as a strategy for enhancing food security, reducing malnutrition, and improving health outcomes on a global scale remains an ongoing subject of profound research interest. Legume seed proteins are rich in their dietary protein contents. However, coexisting with these proteins in the seed matrix are other components that inhibit protein digestibility. Thus, improving access to legume proteins often depends on the neutralisation of these inhibitors, which are collectively described as antinutrients or antinutritional factors. The determination of protein quality, which typically involves evaluating protein digestibility and essential amino acid content, is assessed using various methods, such as in vitro simulated gastrointestinal digestibility, protein digestibility-corrected amino acid score (IV-PDCAAS), and digestible indispensable amino acid score (DIAAS). Since most edible legumes are mainly available in their processed forms, an interrogation of these processing methods, which could be traditional (e.g., cooking, milling, extrusion, germination, and fermentation) or based on emerging technologies (e.g., high-pressure processing (HPP), ultrasound, irradiation, pulsed electric field (PEF), and microwave), is not only critical but also necessary given the capacity of processing methods to influence protein digestibility. Therefore, this timely and important review discusses how each of these processing methods affects legume seed digestibility, examines the potential for improvements, highlights the challenges posed by antinutritional factors, and suggests areas of focus for future research.

Study on model plant based functional beverage emulsion (non-dairy) using ultrasound - A physicochemical and functional characterization

This study reports the development of non-dairy functional beverage emulsion employing ultrasound (US) of 20 kHz at 130 W and 195 W at processing times of 2 to 8 min using chickpea milk extract and bioactive, flaxseed oil (4%). The pre-emulsion was formed with high shear homogenizer followed by main sonication process. The sonicated emulsions were stored at 4 ± 2 °C till 14 days and characterized for physicochemical and functional properties. A comparative study was carried out using conventional high shear homogenizer (UT) at 10,000 RPM for 5 min. Upon optimization, 130 W - 8 min, 195 W - 6 min and 195 W - 8 min sono-emulsions showed creaming stability of 100%; with particle sizes as 1.12, 0.97 and 0.78 µm; and zetapotential values as - 40.4 mV, -37.52 and -36.91 mV, respectively. The improvement in protein solubility by 86% proved the emulsifying capability of chickpea proteins, which had partially denatured upon physical effects of acoustic cavitation producing stable and finer emulsion droplets. The reduced sedimentation values of sonicated chickpea extract in comparison to UT showed improvement in physical stability of plant-based milk. Oxidative stability is observed for 130 W - 8 min sonicated emulsions with no change in conjugated dienes, indicating the absence of process generated free radicals. The US process did not have any effect on reduction of stachyose content. But extracted chickpea milk had lower amount of stachyose in comparison to raw chickpeas, reducing the flatulence problem, mainly due to adaptation of high temperature pressure cooking process.

Enhancing the Biological Activities of Food Protein-Derived Peptides Using Non-Thermal Technologies: A Review

Bioactive peptides (BPs) derived from animal and plant proteins are important food functional ingredients with many promising health-promoting properties. In the food industry, enzymatic hydrolysis is the most common technique employed for the liberation of BPs from proteins in which conventional heat treatment is used as pre-treatment to enhance hydrolytic action. In recent years, application of non-thermal food processing technologies such as ultrasound (US), high-pressure processing (HPP), and pulsed electric field (PEF) as pre-treatment methods has gained considerable research attention owing to the enhancement in yield and bioactivity of resulting peptides. This review provides an overview of bioactivities of peptides obtained from animal and plant proteins and an insight into the impact of US, HPP, and PEF as non-thermal treatment prior to enzymolysis on the generation of food-derived BPs and resulting bioactivities. US, HPP, and PEF were reported to improve antioxidant, angiotensin-converting enzyme (ACE)-inhibitory, antimicrobial, and antidiabetic properties of the food-derived BPs. The primary modes of action are due to conformational changes of food proteins caused by US, HPP, and PEF, improving the susceptibility of proteins to protease cleavage and subsequent proteolysis. However, the use of other non-thermal techniques such as cold plasma, radiofrequency electric field, dense phase carbon dioxide, and oscillating magnetic fields has not been examined in the generation of BPs from food proteins.

Thermal treatment alternatives for enzymes inactivation in fruit juices: Recent breakthroughs and advancements

Fruit juices (FJs) are frequently taken owing to their nutritious benefits, appealing flavour, and vibrant colour. The colours of the FJs are critical indicators of the qualitative features that influence the consumer's attention. Although FJs' intrinsic acidity serves as a barrier to bacterial growth, their enzymatic stability remains an issue for their shelf life. Inactivation of enzymes is critical during FJ processing, and selective inactivation is the primary focus of enzyme inactivation. The merchants, on the other hand, want the FJs to stay stable. The most prevalent technique of processing FJ is by conventional heat treatment, which degrades its nutritive value and appearance. The FJ processing industry has undergone a dramatic transformation from thermal treatments to nonthermal treatments (NTTs) during the past two decades to meet the requirements for microbiological and enzymatic stability. The manufacturers want safe and stable FJs, while buyers want high-quality FJs. According to the past investigation, NTTs have the potential to manufacture microbiologically safe and enzymatically stable FJs with low loss of bioactive components. Furthermore, it has been demonstrated that different NTTs combined with or without other NTTs or mild heating as a hurdle technology increase the synergistic effect for microbiological safety and stability of FJs. Concise information about the variables that affect NTTs' action mode has also been addressed. Primary inactivates enzymes by modifying the protein structure and active site conformation. NTTs may increase enzyme activity depending on the nature of the enzyme contained in FJs, the applied pressure, pH, temperature, and treatment period. This is due to the release of membrane-bound enzymes as well as changes in protein structure and active sites that allow substrate interaction. Additionally, the combination of several NTTs as a hurdle technology, as well as temperature and treatment periods, resulted in increased enzyme inactivation in FJs. Therefore, a combination of thermal and non-thermal technologies is suggested to increase the effectiveness of the process as well as preserve the juice quality.

Moisture Distribution and Structural Properties of Frozen Cooked Noodles with NaCl and Kansui

The effects of NaCl (1-3%) and kansui (0.5-1.5%) on the quality of frozen cooked noodles (FCNs) were investigated, which provided a reference for alleviating the quality deterioration of FCNs. Textural testing illustrated that the optimal tensile properties were observed in 2% NaCl (N-2) and the maximum hardness and chewiness were reached at 1% kansui (K-1). Compared to NaCl, the water absorption and cooking loss of recooked FCNs increased significantly with increasing kansui levels (p < 0.05). Rheological results confirmed NaCl and kansui improved the resistance to deformation and recovery ability of thawed dough; K-1 especially had the highest dough strength. SEM showed N-2 induced a more elongated fibrous protein network that contributed to the extensibility, while excessive levels of kansui formed a deformed membrane-like gluten network that increased the solid loss. Moisture analysis revealed that N-2 reduced the free water content, while K-1 had the lowest freezable water content and highest binding capacity for deeply adsorbed water. The N-2 and K-1 induced more ordered protein secondary structures with stronger intermolecular disulfide bonds, which were maximally improved in K-1. This study provides more comprehensive theories for the strengthening effect of NaCl and kansui on FCNs quality.

Almond By-Products: Valorization for Sustainability and Competitiveness of the Industry

The search for waste minimization and the valorization of by-products are key practices for good management and improved sustainability in the food industry. The production of almonds generates a large amount of waste, most of which is not used. Until now, almonds have been used for their high nutritional value as food, especially almond meat. The other remaining parts (skin, shell, hulls, etc.) are still little explored, even though they have been used as fuel by burning or as livestock feed. However, interest in these by-products has been increasing as they possess beneficial properties (caused mainly by polyphenols and unsaturated fatty acids) and can be used as new ingredients for the food, cosmetic, and pharmaceutical industries. Therefore, it is important to explore almond’s valorization of by-products for the development of new added-value products that would contribute to the reduction of environmental impact and an improvement in the sustainability and competitiveness of the almond industry.

Effects of Pulsed Electric Fields and Ultrasound Processing on Proteins and Enzymes: A Review

There is increasing demand among consumers for food products free of chemical preservatives, minimally processed and have fresh-like natural flavors. To meet these growing demands, the industries and researchers are finding alternative processing methods, which involve nonthermal methods to obtain a quality product that meets the consumer demands and adheres to the food safety protocols. In the past two decades’ various research groups have developed a wide range of nonthermal processing methods, of which few have shown potential in replacing the traditional thermal processing systems. Among all the methods, ultrasonication (US) and pulsed electric field (PEF) seem to be the most effective in attaining desirable food products. Several researchers have shown that these methods significantly affect various major and minor nutritional components present in food, including proteins and enzymes. In this review, we are going to discuss the effect of nonthermal methods on proteins, including enzymes. This review comprises results from the latest studies conducted from all over the world, which would help the research community and industry investigate the future pathway for nonthermal processing methods, especially in preserving the nutritional safety and integrity of the food.

Internal cavity amplification of shell-like ferritin regulated with the change of the secondary and tertiary structure induced by PEF technology

In this study, the effect of pulsed electric field (PEF) on apparent morphology and molecular structure of shell-like ferritin obtained from horse spleen was determined by circular dichroic (CD), fluorescence spectroscopy, Raman spectroscopy, cold field emission scanning electron microscopy (CF-SEM) and transmission electron microscopy (TEM), and verified by molecule dynamics (MD) simulation. After PEF treatment, the α-helix content of the samples reached a minimum value at 10 kV/cm, which indicated that the ferritin structure has been partially unfolded. However, the α-helix content peaked again after resting for 2 h at 25 ± 1 °C. This indicated that the PEF-treated ferritin tended to restore its original spherical morphology probably owing to the reversible assembly characteristic of ferritin. In addition, microstructure analysis revealed that ferritin particles aggregated after PEF treatment. Therefore, PEF treatment could induce the "exposure" of hydrophobic amino acids and conversion of disulfide bond configuration, and consequently, regulate the internal cavity stability of ferritin. The research will be beneficial to expand the application of PEF treatment in the modification of protein structure, and provide a theoretical basis for the application of ferritin as a carrier of bioactive molecules in food.

Physical and Chemical Methods for Reduction in Aflatoxin Content of Feed and Food

Aflatoxins (AFs) are among the most harmful fungal secondary metabolites imposing serious health risks on both household animals and humans. The more frequent occurrence of aflatoxins in the feed and food chain is clearly foreseeable as a consequence of the extreme weather conditions recorded most recently worldwide. Furthermore, production parameters, such as unadjusted variety use and improper cultural practices, can also increase the incidence of contamination. In current aflatoxin control measures, emphasis is put on prevention including a plethora of pre-harvest methods, introduced to control Aspergillus infestations and to avoid the deleterious effects of aflatoxins on public health. Nevertheless, the continuous evaluation and improvement of post-harvest methods to combat these hazardous secondary metabolites are also required. Already in-use and emerging physical methods, such as pulsed electric fields and other nonthermal treatments as well as interventions with chemical agents such as acids, enzymes, gases, and absorbents in animal husbandry have been demonstrated as effective in reducing mycotoxins in feed and food. Although most of them have no disadvantageous effect either on nutritional properties or food safety, further research is needed to ensure the expected efficacy. Nevertheless, we can envisage the rapid spread of these easy-to-use, cost-effective, and safe post-harvest tools during storage and food processing.

Ultrasound-assisted extraction and modification of plant-based proteins: Impact on physicochemical, functional, and nutritional properties

Ultrasonication is a green technology that has recently received an enormous research attention for extraction of plant-based proteins and tailoring the functionalities of these ingredients. Ultrasonication is generally used as a pretreatment method in the conventional protein solubilization protocols because it can break the cell matrix to improve the extractability. The rate of protein extraction and increase in the extraction yields depend on operating conditions such as sonic energy density, time of sonication, the substrate to slurry ratio, agitation, and so on. Ultrasonication is also applied to modify the physical, structural, and functional properties of protein-based ingredients, besides simultaneous extraction and modifications. Significant changes that occur in protein physical properties due to sonication include size reduction, rheology, electrical conductivity, and zeta (ζ) potential. These changes are due to cavitation-induced shear leading to changes in secondary and tertiary structures, including protein aggregation and cross-linking due to oxidation. Physical and structural changes affect the resulting ingredient functionality and nutritional quality of protein. Changes in the functional properties, especially hydrophobicity, solubility, emulsion, and foaming, depend on the extent of ultrasound energy applied to the protein. This study aims to review major ultrasound process parameters and conditions for extraction and modification of plant proteins and their impact on protein structural changes and resulting physicochemical, functional, and nutritional properties.