Ultrasound Pretreatment Increases the Bioavailability of Dietary Proteins by Dissociating Protein Structure and Composition

Effect of sonoprocessing on the quality of plant-based analog foods: Compatibility to sustainable development goals, drawbacks and limitations

Sonoprocessing (US), as one of the most well-known and widely used green processing techniques, has tremendous benefits to be used in the food industry. The urgent call for global sustainable food production encourages the usage of such techniques more often and effectively. Using ultrasound as a hurdle technology synergistically with other green methods is crucial to improving the efficiency of the protein shift as well as the number of plant-based analog foods (PBAFs) against conventional products. It was revealed that the US has a significant impact when used as an assistant tool with other green technologies rather than being used alone. It increases the protein extraction efficiencies from plant biomasses, improves the techno-functional properties of food compounds, and makes them more applicable for industrial-scale alternative food production in the circular economy. The US aligns well with the objectives outlined in the UN's Sustainable Development Goals (SDGs), and Planetary Boundaries (PBs) framework, demonstrating promising outcomes in life cycle assessment. However, several challenges such as uncontrolled complex matrix effect, free radical formation, uncontrolled microbial growth/germination or off-flavor formation, removal of aromatic compounds, and Maillard reaction, are revealed in an increased number of studies, all of which need to be considered. In addition to a variety of advantages, this review also discusses the drawbacks and limitations of US focusing on PBAF production.

Effects of microfluidization time on the structural, physiochemical and functional properties of walnut protein

The effect of microfluidization treatment time under a pressure of 1 MPa on the structural, physiochemical and functional properties of walnut protein (WP) were evaluated. The results showed that the particle size of WP was significantly reduced by 102.10 % and the absolute zeta potential, solubility, water holding capacity, foaming capacity and stability increased by 336.41 %, 170.69 %, 27.67 g/g, 302.07 % and 334.23 %, respectively, when the microfluidization treatment time was 15 min (P < 0.05). And the oil holding capacity, emulsion capacity and stability of the WP increased from 1.19 g/g to 1.81 g/g, from 34.48 % and 78.82 % to 57.52 % and 98.86 %, respectively. With the extend of microfluidization treatment time, the secondary structure percentages of WP were altered. The WP after microfluidization treatment had optimal gastric digestion, while the intestine digestion was the worst. The amino acid results indicated the microfluidization treatment time did not affect the nutritional quality of WP.

Protein from tiger nut meal extracted by deep eutectic solvent and alkali-soluble acid precipitation: A comparative study on structure, function, and nutrition

Protein from tiger nut meal (TNP) performance high nutritional value. This study optimized the extraction parameters for TNP (DES-TNP) using deep eutectic solvent, with HBD: HBA = 5:1, Liquid: Solid = 11:1, and the moisture content was 15 %. A comprehensive comparison was conducted with the protein extracted using alkali-soluble acid precipitation (ASAE-TNP). DES-TNP demonstrated significantly higher purity (76.21 ± 2.59 %) than ASAE-TNP (67.48 ± 1.11 %). Density functional theory confirmed the successful synthesis of DES and its strong interaction with TNP. Moreover, DES-TNP and ASAE-TNP were different in structure (microscopic, secondary, and tertiary) and molecular weight distribution. The discrepancy contributed to the different functional properties, DES-TNP exhibiting better solubility, emulsification and foaming properties at pH13 compared to ASAE-TNP. For nutritional properties, DES-TNP and ASAE-TNP exhibited similar amino acid composition and digestibility, but the total amino acid content of DES-TNP was higher. This study presented a novel method for the extraction and comprehensive utilization of TNP.

The Effect of Ultrasound Treatment on the Structural and Functional Properties of Tenebrio molitor Myofibrillar Protein

The objective of this study was to explore the impacts of various ultrasonic powers (0, 300, 500, 700, and 900 W) on the structure and functional attributes of the myofibrillar protein (MP) of Tenebrio molitor. As the ultrasonic intensity escalated, the extraction efficiency and yield of the MP rose, while the particle size and turbidity decreased correspondingly. The reduction in sulfhydryl group content and the increase in carbonyl group content both suggested that ultrasonic treatment promoted the oxidation of the MP to a certain extent, which was conducive to the formation of a denser and more stable gel network structure. This was also affirmed by SEM images. Additionally, the findings of intrinsic fluorescence and FTIR indicated that high-intensity ultrasound significantly altered the secondary structure of the protein. The unfolding of the MP exposed more amino acid residues, the α-helix decreased, and the β-helix improved, thereby resulting in a looser and more flexible conformation. Along with the structural alteration, the surface hydrophobicity and emulsification properties were also significantly enhanced. Besides that, SDS-PAGE demonstrated that the MP of T. molitor was primarily composed of myosin heavy chain (MHC), actin, myosin light chain (MLC), paramyosin, and tropomyosin. The aforementioned results confirmed that ultrasonic treatment could, to a certain extent, enhance the structure and function of mealworm MP, thereby providing a theoretical reference for the utilization of edible insect proteins in the future, deep-processing proteins produced by T. molitor, and the development of new technologies.

The emergence of cancer sono-immunotherapy

Owing to its remarkable ease of use, ultrasound has recently been explored for stimulating or amplifying immune responses during cancer therapy, termed 'sono-immunotherapy'. Ultrasound can cause immunogenic cell death in cancer cells via thermal and nonthermal effects to regulate the tumor microenvironment, thereby priming anticancer immunity; by integrating well-designed biomaterials, novel sono-immunotherapy approaches with augmented efficacy can also be developed. Here, we review the advances in sono-immunotherapy for cancer treatment and summarize existing limitations along with potential trends. We offer emerging insights into this realm, which might prompt breakthroughs and expand its potential applications to other diseases.

Protein Nutrition: Understanding Structure, Digestibility, and Bioavailability for Optimal Health

This review discusses different protein sources and their role in human nutrition, focusing on their structure, digestibility, and bioavailability. Plant-based proteins, such as those found in legumes, nuts, and seeds, may contain anti-nutritional factors that impact their bioavailability apart from structural and compositional differences from animal proteins. Animal proteins are generally highly digestible and nutritionally superior to plant proteins, with higher amino acid bioavailability. Alternative protein sources are also processed in different ways, which can alter their structure and nutritional value, which is also discussed.

Enhancing the Gelation Behavior of Transglutaminase-Induced Soy Protein Isolate(SPI) through Ultrasound-Assisted Extraction

Gelation, as an important functional property of soy protein isolate (SPI), can be improved by some green technologies in food manufacturing, including ultrasound, ultrahigh pressure and microwave treatments. This work investigated the effect of an alkaline solubilisation step in SPI extraction combined with sonication on protein properties. The TGase-induced gel of the modified SPI was prepared to explore the effect of ultrasound on gel properties, including structures, strength, water-holding capacity and rheological properties. Additionally, the differences between traditional ultrasound modification of SPI and current modification methods were analyzed. The results showed that the ultrasonication-assisted extraction method could result in a significant increase in extraction rate from 24.68% to 42.25%. Moreover, ultrasound-assisted modification of SPI gels induced with transglutaminase (TGase) exhibited significant improvement in mechanical properties, such as texture, water-holding capacity and rheological properties, In particular, SPI extracted at 400 W ultrasound intensity for 180 s showed the best overall performance in terms of gel properties. Our method efficiently uniformizes gel structure, enhancing mechanical properties compared to conventional ultrasound methods, which reduced energy consumption and costs. These findings provide insights into the production of high-gelation SPI in food manufacturing.

Time-specific ultrasonic treatment of litchi thaumatin-like protein inhibits inflammatory response in RAW264.7 macrophages via NF-κB and MAPK transduction pathways

The pro-inflammation activity of litchi thaumatin-like protein (LcTLP) led to be responsible for the occurrence of adverse reactions after excessive consumption of litchi. This study aimed to characterize the changes in the structure and inflammatory activity of LcTLP induced by ultrasound treatment. Significant molecular structure of LcTLP changes occured at 15 min ultrasound treatment, and then tended to recover with subsequent treatment. Secondary structure (α-helices decreased from 17.3% to 6.3%), tertiary structure (the maximum endogenous fluorescence intensity decreased), and microstructure (mean hydrodynamic diameter reduced from 4 μm to 50 nm) of the LcTLP treated for 15 min (LT15) were significantly affected, which led to the inflammatory epitope of LcTLP (domain II and V-cleft) unfolded. In vitro, LT15 had a significant anti-inflammatory response, which inhibited NO production and had the best effect at 50 ng/mL in RAW264.7 macrophages (73.24%). Moreover, proinflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) secretion and mRNA expression levels were also significantly lower compared with untreated LcTLP (p < 0.05). Western blot further confirmed that the expressions of IκB-α, p65, p38, ERK and JNK reduced markedly (p < 0.05), which indicated LT15 inhibited the inflammatory response through NF-κB and MAPK transduction pathways. Overall, it can be hypothesized that LT15 exposed to low frequency ultrasonic fields have a direct effect on the protein surface structure and thus on the entry of LT15 into cells, making 15-minute ultrasound treatment potentially useful in reducing the pro-inflammatory properties of litchi or related liquid products.

Comparison of protein in vitro digestibility under adult and elderly conditions: The case study of wheat, pea, rice, and whey proteins

In this study an in vitro static digestion method mimicking the elderly gastrointestinal conditions was designed by adapting the physiological parameters described in the INFOGEST standardized static in vitro digestion protocol, i.e., pH, digestive phase duration, concentrations of enzymes and bile salts, to the aged GI transit. The digestibility of proteins from different sources (pea, rice, wheat, and milk whey) was then assessed. Protein digestive behaviour was monitored after gastric and intestinal phases by BCA assay and SDS-PAGE to assess protein hydrolysis both from a quantitative and a qualitative point of view. Digested samples were also analysed for physical characteristics in terms of particle size and zeta potential. Data acquired under elderly gastrointestinal conditions were compared to those obtained by using the INFOGEST protocol designed to study adult digestion. Results clearly showed that the elderly gastrointestinal conditions deeply affected proteolysis leading to a general reduction of protein digestibility in comparison to the adult model. The proteolysis extent depended on the protein source with whey and rice proteins showing about 20% reduction using the model mimicking the elderly gut, followed by pea (about 10% reduction) and wheat (about 4% reduction) proteins. The knowledge of protein digestibility under elderly gastrointestinal conditions generated in this study could be useful in the attempt to develop age-tailored products.

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.

Influence of high-intensity ultrasound on physicochemical and functional properties of a guamuchil Pithecellobium dulce (Roxb.) seed protein isolate

In this study, the influence of ultrasound on the physicochemical and functional properties of guamuchil seed protein isolate (GSPI) was investigated. The GSPI was prepared by alkaline extraction and isoelectric precipitation method followed by treating with ethanol (95%), from defatted guamuchil seed flour. GSPI suspensions (10%) were sonicated with a probe (20 kHz) at 3 power levels (200 W, 400 W, 600 W) for 15 and 30 min, in addition, to control treatment without ultrasound. Moisture content, water activity, bulk and compact densities and the L*, a* and b* color parameters of the GSPI decreased due to the ultrasound. Glutelin (61.1%) was the main protein fraction in GSPI. Results through Fourier transform infrared and fluorescence spectroscopy showed that ultrasound modified the secondary and tertiary protein structures of GSPI, which increased the surface hydrophobicity, molecular flexibility and in vitro digestibility of GSPI proteins by up to 114.8%, 57.3% and 12.5%, respectively. In addition, maximum reductions of 11.9% in particle size and 55.2% in turbidity of GSPI suspensions, as well as larger and more porous aggregates in GSPI lyophilized powders were observed by ultrasound impact. These structural and physicochemical changes had an improvement of up to 115.5% in solubility, 39.8% in oil absorption capacity, while the increases for emulsifying, foaming, gelling, flow and cohesion properties of GSPI were 87.4%, 74.2%, 40.0%, 44.4%, and 8.9%, respectively. The amelioration of the functional properties of GSPI by ultrasound could represent an alternative for its possible use as a food ingredient in industry.

The Preparation, Antioxidant Activity Evaluation, and Iron-Deficient Anemic Improvement of Oat (Avena sativa L.) Peptides-Ferrous Chelate

Iron-chelating peptides have been widely considered as one of the best iron supplements to alleviate the iron deficiency. In this study, a novel oat peptides-ferrous (OP-Fe2+) chelate was prepared from antioxidant oat peptides obtained in the laboratory of the authors. The optimal preparation condition was obtained through the single-factor and response surface methodology, and the chelating rate could reach up to 62.6%. After chelation, the OP-Fe2+ chelate exhibited a significantly higher 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity than oat peptides. It was discovered that the hemoglobin concentration and the number of red blood cell levels in OP-Fe2+-treated iron-deficient anemic (IDA) rats were significantly higher than untreated IDA rats. The OP-Fe2+ chelate could also improve the hypertrophy of the spleen, serum iron (SI), total iron and binding capacity, and serum ferritin levels in the IDA rats. In addition, the OP-Fe2+ treatment significantly increased the antioxidant activities of super oxidase and glutathione in the liver homogenate of the IDA rats. Therefore, the OP-Fe2+ chelate is an effective type of iron supplement for IDA rats, which could be a promising source with anti-anemia and antioxidant activity.

Impact of Innovative Technologies on the Content of Vitamin C and Its Bioavailability from Processed Fruit and Vegetable Products

Nowadays, thermal treatments are used for extending the shelf-life of vegetable and fruit products by inactivating microorganisms and enzymes. On the other hand, heat treatments often induce undesirable changes in the quality of the final product, e.g., losses of nutrients, color alterations, changes in flavor, and smell. Therefore, the food industry is opening up to new technologies that are less aggressive than thermal treatment to avoid the negative effects of thermal pasteurization. Non-thermal processing technologies have been developed during the last decades as an alternative to thermal food preservation. Processing changes the structure of fruit and vegetables, and hence the bioavailability of the nutrients contained in them. In this review, special attention has been devoted to the effects of modern technologies of fruit and vegetable processing, such as minimal processing (MPFV), high-pressure processing (HPP), high-pressure homogenization (HPH), ultrasounds (US), pulsed electric fields (PEF), on the stability and bioavailability of vitamin C.