Functional Proteins from Biovalorization of Peanut Meal: Advances in Process Technology and Applications.

Environmental costs associated with meat production have necessitated researchers and food manufacturers to explore alternative sources of high-quality protein, especially from plant origin. Proteins from peanuts and peanut-by products are high-quality, matching industrial standards and nutritional requirements. This review contributes to recent developments in the production of proteins from peanut and peanut meal. Conventional processing techniques such as hot-pressing kernels, use of solvents in oil removal, and employing harsh acids and alkalis denature the protein and damage its functional properties, limiting its use in food formulations. Controlled hydrolysis (degree of hydrolysis between 1 and 10%) using neutral and alkaline proteases can extract proteins and improve peanut proteins' functional properties, including solubility, emulsification, and foaming activity. Peanut proteins can potentially be incorporated into meat analogues, bread, soups, confectionery, frozen desserts, and cakes. Recently, pretreatment techniques (microwave, ultrasound, high pressure, and atmospheric cold plasma) have been explored to enhance protein extraction and improve protein functionalities. However, most of the literature on physicochemical pretreatment techniques has been limited to the lab scale and has not been analysed at the pilot scale. Peanut-derived peptides also exhibit antioxidant, anti-hypertensive, and anti-thrombotic properties. There exists a potential to incorporate these peptides into high-fat foods to retard oxidation. These peptides can also be consumed as dietary supplements for regulating blood pressure. Further research is required to analyse the sensory attributes and shelf lives of these novel products. In addition, animal models or clinical trials need to be conducted to validate these results on a larger scale.

Identification of allergens and allergen hydrolysates by proteomics and metabolomics: A comparative study of natural and enzymolytic bee pollen.

Bee pollen as a plant-derived food is consumed as nutritional/functional supplements by humans. But it might confer foodborne allergenicity in susceptible populations, limiting its extensive application. In this study, five potential allergens including profilin, cystatin, prolamin, expansin, and alcohol dehydrogenase in bee pollen derived from Brassica campestris (BP-Bc), were identified through mass spectrometry-based proteomic analysis. Moreover, different types of enzymes (cellulases, pectases, and papains) serve biological roles in pollen wall breaking and expansion, but also promote allergen release and degradation. Proteomic analysis showed that profilin, cystatin, and alcohol dehydrogenase were significantly reduced in BP-Bc following joint treatment with three enzymes. Metabolomic characterization of potential enzymatic hydrolysates of these significantly-decreased allergens was performed, which showed nine major oligopeptides and six amino acids at significantly higher levels in the enzyme-treated BP-Bc. These findings clarified the culprit responsible for bee pollen allergy and the mechanism of enzymatic desensitization for its further development.

Pretreatment of buckwheat globulin by ultra-high pressure: Effects on enzymatic hydrolysis and final hydrolysate lipid metabolism regulation capacities.

The purpose of this study was to evaluate the effects of ultra-high pressure (UHP) pretreatment on the buckwheat globulin and the regulation of lipid metabolism disorder by its enzymatic hydrolysates (BGH). Buckwheat globulin hydrolysates pretreated by ultra-high pressure (UBGH) can significantly reduce the levels of total triglyceride (TG) and total cholesterol (TC) in model cells (MOD), significantly inhibit lipid accumulation and steatosis. In addition, UBGH can significantly reduce the content of malondialdehyde (MDA), increase the activity of total superoxide dismutase (T-SOD) and total antioxidant capacity (T-AOC), thus reducing the vicious cycle of lipid metabolism disorder caused by oxidative stress. RT-PCR and western blotting analysis showed that after UBGH intervention, compared with the MOD group, the mRNA expression levels of liver lipid and cholesterol metabolism related genes were significantly changed. UBGH significantly increased PPARα and LXRα and decreased SREBP2 mRNA expression. Therefore, UHP technology could enhance the regulatory effect of BGH on lipid metabolism disorder.

Preparation of the Enzymatic Hydrolysates from Chlorella vulgaris Protein and Assessment of Their Antioxidant Potential Using Caenorhabditis elegans.

This study aimed to assess the antioxidant potential of Chlorella vulgaris protein-derived enzymatic hydrolysate using Caenorhabditis elegans. Protein extraction was performed using an alkali solution after complete C. vulgaris swelling and hydrolysis using four commercial proteases (alcalase, neutrase, protamex, and flavourzyme). The results showed that the flavourzyme hydrolysates exhibited the strongest antioxidant activity both in vitro and in vivo. Under the optimum conditions of the enzymatic hydrolysis, the half-maximal effective concentration of the hydrolysates for superoxide and hydroxyl radicals was 0.323 mg/mL and 0.139 mg/mL, respectively. The hydrolysates could significantly extend the lifespan, improve the resistance to methyl viologen-induced oxidative stress, reduce the levels of reactive oxygen species, and enhance the activity of catalase and superoxide dismutase in C. elegans.

Pseudocereals: a novel source of biologically active peptides.

The interest in the research about underexploited foods has increased in the last two decades. Pseudocereals have been consumed by the ancient populations for hundreds of years. These plants that do not belong to the family of cereals, but that have properties and uses similar to them, stand out among underexploited foods. Some of the most representative species are quinoa, amaranth, chia and buckwheat. They do not contain gluten but high valued proteins and peptides can be obtained from them, as well as other nutritional and bioactive compounds such as flavonoids, phenolic acids, fatty acids, vitamins and minerals. Anticancer, antioxidant, anti-inflammatory, hypocholesterolemic and antihypertensive properties have been found and postulated for pseudocereals protein derived peptides. These interesting characteristics of pseudocereals are producing an increase of the relevance of these crops. The purpose of this work was to carry out an exhaustive revision of the scientific literature describing the biological activities of peptides and protein hydrolysates obtained from the most widely studied pseudocereals: quinoa, amaranth, chia and buckwheat.

[Enzymatic hydrolysates of food proteins for specialized foods for therapeutic and prophylactic nutrition].

The review considers some issues of obtaining, as well as physic-chemical, organoleptic, immunochemical (residual antigenicity) characteristics of enzymatic hydrolysates from food proteins (EHFP) that are widely used in food products for various purposes, as well as assessing their biological activity. The results of experimental works and patents, which describe the most widely used approaches to the production of EHFP with desired properties (hydrolysates for therapeutic and prophylactic products), as well as assessments of biological activity and immunochemical properties are given. The use of various enzyme preparations (of bacterial, fungal and animal origin), as well as one- and two-stage hydrolysis schemes and options for instrumentation of fermentolysis processes are considered. It is concluded that in order to achieve the required reduction in antigenicity for hydrolysates used as part of therapeutic (hypoallergenic) foods (to values not higher than 10-5 relative to the antigenicity of the original protein) membrane ultrafiltration stages are necessary. The main disadvantage of such hydrolysates is their unsatisfactory organoleptic properties (bitterness and high osmolarity) that can be improved using a number of additional technological approaches. The use of partial hydrolysates (or hydrolysates with an average degree of hydrolysis, with a residual antigenicity of 10-4 to 10-5) with significantly better organoleptic properties compared with deep hydrolysates in therapeutic foods is considered. Of considerable interest are the issues of immunomodulatory, antioxidant and hypoallergenic properties of EHFP. It has been suggested that soybean and chicken egg hydrolysates may be promising as functional ingredients with antimicrobial, antihypertensive and immunomodulatory effects in various specialized foods, as well as in cases of food intolerance only to cow milk proteins.

[Experimental evaluation of hypolipidemic properties of soy and rice proteins and their enzyme hydrolysates. A brief review].

Metabolic syndrome (MS) is characterized with high prevalence, constant increase of people suffering from this disease and high rate of cardiovascular complications. The key factors, leading to the development of metabolism disorders during MS, are visceral fat mass growth and decrease in sensitivity of peripheral tissues to insulin, which are associated with disorders of carbohydrate, lipid, purine metabolism and arterial hypertension. The main results of in vivo studies of hypolipidemic properties of soy protein, rice bran protein and their enzymatic hydrolysates using laboratory rats and mice with experimentally induced or genetically associated dyslipidemia are presented in this review. The analysis of reviewed publications shows that consumption of soy protein provides body weight loss, normalizes lipid metabolism, reduces insulin resistance. The consumption of rice protein by laboratory animals, as well as soy protein, leads to decrease of serum cholesterol level and also provides steroid excretion, such as cholesterol and bile acids, with feces. Enzymatic hydrolysis of food proteins allows obtaining peptide mixtures with high biological value and improved functional properties, especially water solubility and intestinal absorption. In their turn, hypolipidemic peptides of hydrolysates can play a key role in endogenous cholesterol homeostasis by means of disturbing its micellar solubility, intestinal absorption, changing bile acids entherohepatic circulation, and also lowering the expression of some genes of proteins - mediators of lipid transport. It has been concluded, that hypolipidemic properties of obtained enzymatic hydrolysates of food proteins determine the prospects of their use in specialized food products for prevention of metabolic disorders.

Isolation and identification of antioxidant peptides from enzymatically hydrolyzed rice bran protein.

Khao Dawk Mali 105 rice bran protein (RBP) was fractionated into albumin (12.5%), globulin (13.9%), glutelin (70.8%) and prolamine (2.9%). The native and denatured RBP fractions were hydrolyzed with papain and trypsin for 3h at optimum conditions. The RBP fractions and their hydrolysates were evaluated for their antioxidant activity by the Oxygen Radical Absorbance Capacity (ORAC) assay. The trypsin-hydrolyzed denatured albumin exhibited the highest antioxidant activity with an ORAC value of 4.07 µmol of Trolox equivalent (TE)/mg protein. This hydrolysate was separated by using RP-HPLC and three fractions with high antioxidant activity were examined by LTQ-FTICR ESI mass spectrometry. The MW of the peptides from these fractions were 800-2100 Da. and consisted of 6-21 amino acid residues. Most of the peptides from the fractions demonstrated typical characteristics of well-known antioxidant peptides. The results suggest that trypsin-hydrolyzed denatured rice bran albumin might be useful as a natural food antioxidant.