Assessment of soy genotype and processing method on trypsin inhibitors, urease and lectins content of tofu.

Tofu has a high nutritional value, but it may also contain components that may have an antinutritional effect, such as trypsin inhibitors (TI), lectins and ureases. The aim of this study was to investigate the influence of the hydrothermal-cooking process of soybean in combination with commercial chymosin-pepsin rennet on the content and activity of TI, urease and lectins in tofu. High total TI content was found in tofu (5.00-16.87%). In addition, Kunitz (KTI = 3.52-4.32%) and Bowman-Birk (BBI = 5.00-12.53%) TI were registered, and BBI was detected in polymeric (1.38-2.71%) and monomeric (3.42-9.82%) forms. TI activity of tofu was very low (5.86-9.34%), corresponding to the very low activity of urease (0.51-3.07%). The percentage of lectin (2.62-4.63%) and urease (0.03-0.12%) in tofu was low. The results showed that the applied tofu production process is very effective in reducing the content and activity of TI, urease and lectin and provides the values without nutritional harmful effect.

Monofloral Corn Poppy Bee-Collected Pollen-A Detailed Insight into Its Phytochemical Composition and Antioxidant Properties.

The aim of this study was to compile a detailed phytochemical profile and assess the antioxidant properties of bee-collected pollen (PBP) obtained from corn poppy (Papaver rhoeas L.) plants. To achieve this, a lipid fraction was prepared for quantifying fatty acids using GC-FID. Extractable and alkaline-hydrolysable PBP fractions (obtained from a defatted sample) were used to determine the qualitative and quantitative profiles of phenolic compounds, phenylamides and alkaloids using UHPLC/Q-ToF-MS. Additionally, various spectrophotometric assays (TAC, FRP, CUPRAC, DPPH⦁) were conducted to evaluate the antioxidant properties. Phenolic compounds were more present in the extractable fraction than in the alkaline-hydrolysable fraction. Luteolin was the predominant compound in the extractable fraction, followed by tricetin and various derivatives of kaempferol. This study presents one of the first reports on the quantification of tricetin aglycone outside the Myrtaceae plant family. The alkaline-hydrolysable fraction exhibited a different phenolic profile, with a significantly lower amount of phenolics. Kaempferol/derivatives, specific compounds like ferulic and 5-carboxyvanillic acids, and (epi)catechin 3-O-gallate were the predominant compounds in this fraction. Regarding phenylamides, the extractable fraction demonstrated a diverse range of these bioactive compounds, with a notable abundance of different spermine derivatives. In contrast, the hydrolysable fraction contained six spermine derivatives and one spermidine derivative. The examined fractions also revealed the presence of seventeen different alkaloids, belonging to the benzylisoquinoline, berberine and isoquinoline classes. The fatty-acid profile confirmed the prevalence of unsaturated fatty acids. Furthermore, both fractions exhibited significant antioxidant activity, with the extractable fraction showing particularly high activity. Among the assays conducted, the CUPRAC assay highlighted the exceptional ability of PBP's bioactive compounds to reduce cupric ions.

Okara-Enriched Gluten-Free Bread: Nutritional, Antioxidant and Sensory Properties.

The aim of this study was to produce an eco-innovative gluten-free bread with a pleasant taste and a unique formulation that includes the highest quality grains and pseudocereals (buckwheat; rice; and millet); and okara; a by-product of soy milk production. The mixture of pseudocereal and cereal flour contained buckwheat flour 45%, rice flour 33%, and millet flour 22%. Three gluten-free breads; each containing different contents of gluten-free flour (90%, 80%, and 70%, respectively); okara (10%, 20%, and 30%, respectively); and a control sample (without okara); were prepared and subjected to sensory evaluation. The okara-enriched gluten-free bread with the highest sensory score was selected for further analysis of physico-chemical (total proteins; total carbohydrates; insoluble fiber; soluble fiber; sugars; total lipids; saturated fatty acids; and salt) and functional properties (total phenolic content and antioxidant properties). The highest sensory scores were obtained for 30% okara-enriched gluten-free bread including taste; shape; odor; chewiness; and cross-section properties; classifying this bread in the category of very good quality and excellent quality (mean score 4.30 by trained evaluators and 4.59 by consumers). This bread was characterized by a high content of dietary fiber (14%), the absence of sugar; low content of saturated fatty acids (0.8%), rich source of proteins (8.8%) and certain minerals (e.g.,; iron; zinc); and low energy value (136.37 kcal/100g DW). Total phenolic content was 133.75 mgGAE/100g FW; whereas ferric reducing power; ABTS radical cation; and DPPH radical scavenging activity were 119.25 mgAA/100g FW; 86.80 mgTrolox/100g FW; and 49.92 mgTrolox/100g FW; respectively. Okara addition in gluten-free bread production enables the formulation of high-nutritive; good antioxidative; low-energy bread; and better soy milk waste management.

Composition of proteins in fresh whey as waste in tofu processing.

Tofu whey is a pale-yellowish liquid with specific aroma/taste which remains as the byproduct/waste after tofu squeezing and represents an environmental problem for direct disposal. Understanding the fresh tofu whey protein composition and the activity of bioactive peptides could be useful for the application of tofu whey as a functional food additive. Tofu whey was obtained during the tofu production from six soybean genotypes by hydrothermal processing in combination with chymosin-pepsin rennet. Basic 7S globulin (14.28-19.13%), γ-conglycinin (7.73-9.31%) and ß-conglycinin (10.59-12.90%) were registered of the total extracted proteins. Glycinin was present with a dominant share of acidic (24.64-27.55%) versus basic polypeptides (12.18-14.61%) in the total extracted proteins. High content of total protein (22.67-28.00%), balanced content (9.76-13.33% of the total extracted proteins) and residual activity (1.95-3.76%) of trypsin inhibitors and low lectins content (5.04-5.48% of the total extracted proteins) indicate good nutritional value of the tofu whey samples. Tofu whey can be potentially useful for application as a cheap, nutritional and functional food additive and can enable sustainable production through the recycling of waste.

Micro/trace/toxic elements and insecticide residues level in monofloral bee-collected sunflower pollen- health risk assessment.

The aim of the current research was to determine the content of (potentially) toxic elements and insecticide residues in monofloral sunflower bee-collected pollen. For micro- and trace elements determination Inductively Coupled Plasma Optical Emission (ICP-OES) analytical method was used while insecticide residue content was monitored by applying Liquid Chromatography-Mass Spectrometry (LC-MS/MS) technique. In total, seventeen micro/trace elements were quantified. None of the twenty four examined insecticides were detected above the limit of detection (LOD) which makes studied sunflower bee-collected pollen eco-friendly both to bees and humans. Based on presence of several toxic as well as potentially toxic elements calculations for estimated weekly intakes (EWI), and oral intakes (OI) were made and used for health risk assessment based on the computation of two different health risk quotients (HQ)- acute (HQA) and long-term (HQL). The obtained results proved that all HQ values for adults were negligible or low except in case of HQL value for arsenic (0.32) which can be characterized as medium. However, in case of children much more precaution is needed due to significant HQL risk for arsenic (1.511). The attained data can help to make additional linkage between bee-collected pollen as food ingredients and potential benefits/risks for human health.

Trypsin inhibitor content and activity of soaking water whey as waste in soy milk processing.

Soybean soaking water whey (SWW) is obtained as the waste of soy milk production and mostly represents an environmental problem. The aim of this study was to assess the content of proteins and content and activity of trypsin inhibitors of fresh SWW, obtained during soy milk production. Two zones of Bowman-Birk trypsin inhibitors (BBI) were detected. One was identified as a monomeric form of BBI (0.61-2.93%) and the other one was identified as a polymeric form of BBI (0.45-3.33%). The degree of BBI extraction (1.88-5.49%) was influenced by the soybean genotype and the grain size, i.e. it increased with increasing grain size. Kunitz trypsin inhibitor was not detected. Total proteins were found in traces in SWW (0.03-0.06%). Low residual trypsin inhibitor activity (0.32-0.55%) suggested that SWW can potentially be applied for preparing food or feed. In that case it will not be waste but a cheap functional supplement with BBI as a biologically active component.

Mycotoxins and Mycotoxin Producing Fungi in Pollen: Review.

Due to its divergent chemical composition and good nutritional properties, pollen is not only important as a potential food supplement but also as a good substrate for the development of different microorganisms. Among such microorganisms, toxigenic fungi are extremely dangerous as they can synthesize mycotoxins as a part of their metabolic pathways. Furthermore, favorable conditions that enable the synthesis of mycotoxins (adequate temperature, relative humidity, pH, and aw values) are found frequently during pollen collection and/or production process. Internationally, several different mycotoxins have been identified in pollen samples, with a noted predominance of aflatoxins, ochratoxins, fumonisins, zearalenone, deoxynivalenol, and T-2 toxin. Mycotoxins are, generally speaking, extremely harmful for humans and other mammals. Current EU legislation contains guidelines on the permissible content of this group of compounds, but without information pertaining to the content of mycotoxins in pollen. Currently only aflatoxins have been researched and discussed in the literature in regard to proposed limits. Therefore, the aim of this review is to give information about the presence of different mycotoxins in pollen samples collected all around the world, to propose possible aflatoxin contamination pathways, and to emphasize the importance of a regular mycotoxicological analysis of pollen. Furthermore, a suggestion is made regarding the legal regulation of pollen as a food supplement and the proposed tolerable limits for other mycotoxins.

Phytochemical Analysis and Total Antioxidant Capacity of Rhizome, Above-Ground Vegetative Parts and Flower of Three Iris Species.

This study was aimed at investigating the phytochemical composition and antioxidant capacity of rhizomes, above-ground vegetative parts and flowers of three Iris species: Iris humilis Georgi, Iris pumila L. and Iris variegata L. UHPLC-Orbitrap MS analysis was used for determination of phytochemical profile. Total pigments, phenolics, flavonoids, soluble sugars and starch content as well as ABTS antioxidant capacity were also determined. In total, 52 phenolics compounds were identified with 9 compounds (derivatives of iriflophenone, apigenin C-glycosides, luteolin O-glycoside, isoflavones derivatives of iristectorigenin, dichotomitin, nigracin and irilone) never reported before in Iris spp. Differences in phenolic composition profile, pigments, soluble sugar, starch, total phenolics and flavonoids content and total antioxidant capacity were found among Iris species and different part of plants. Significant correlation between total phenolic content and antioxidant capacity was determined. The obtained results are comparable with those obtained for medical plants. These findings could be useful for fingerprinting characterization of Iris species and estimation of possible use in pharmaceutical industries.

Comparative study of the functional properties of three legume seed isolates: adzuki, pea and soy bean.

The aim of this work was to compare functional properties including solubility, emulsifying and foaming properties of native and thermally treated adzuki, soy and pea protein isolates prepared under the same conditions. These functional properties were tested at four pH values: pH 3.0, pH 5.0, pH 7.0 and pH 8.0. The lowest solubility at all pH values were obtained for isolate of adzuki whereas isolates of soybean had the highest values at almost all pHs. Thermal treatment reduced solubility of soy and pea isolates at all pH values, whereas solubility of adzuki isolate was unchanged, except at pH 8. Native isolate of adzuki had the best emulsifying properties at pH 7.0 whereas at the other pH values some of native pea and soybean protein isolates were superior. After thermal treatment, depending on tested pH and selected variety all of three species could be a good emulsifier. Native soy protein isolates formed the most stable foams at all pHs. Thermal treatment significantly improved foaming properties of adzuki isolate, whereas reduced foaming capacity of soy and pea isolates, but could improve foam stability of these isolates at specific pH. Appropriate selection of legume seed as well as variety could have great importance in achievement of desirable functional properties of final products. All three tested species could find specific application in wide range of food products.

Mineral elements, lipoxygenase activity, and antioxidant capacity of okara as a byproduct in hydrothermal processing of soy milk.

Minerals and antioxidative capacity of raw okara that was obtained as a byproduct from six soybean varieties during hydrothermal cooking (HTC) of soy milk were assessed. Lipoxygenase (Lox), an enzyme deteriorating the sensory characteristics of okara, was also investigated. All genotypes had very similar concentrations of Lox (4.32-5.62%). Compared to raw soybeans, the applied HTC significantly reduced Lox content in okara (0.54-0.19%) and lowered its activity to 0.004-0.007 µmol g(-1) min (-1). Correlation between the content of Lox in soybeans and that in okara (r = 0.21;p < 0.05) was not registered. This indicates that the content of this enzyme in okara depended much more on the technological process than on soybean genotype. Very strong correlation (r = 0.99; p < 0.05) between okara Lox content and its activity was found. The most abundant minerals in raw okara were potassium (1.04-1.21 g/100g), phosphorus (0.45-0.50 g/100 g), calcium (0.26-0.39 g/100 g), and iron (5.45-10.95 mg/100 g). A very high antioxidant capacity (19.06-29.36 mmol Trolox kg(-1)) contributes to the nutritional value of raw okara.

Bioactive proteins and energy value of okara as a byproduct in hydrothermal processing of soy milk.

The nutritional properties of raw okara obtained as a byproduct from six soybean varieties during hydrothermal cooking (HTC) of soy milk were assessed. The composition and residual activity (rTIA) of trypsin inhibitors (TIs), contents of lectin, proteins, fats, and carbohydrates, and energy values (EV) were correlated with the respective physicochemical properties of soybean and okara. Kunitz (KTI) and Bowman-Birk (BBI) TIs both comprised okara rTIA. TIs content was higher in okara (5.19-14.40%) than in soybean (3.10-12.17%), which additionally enriched okara by cysteine. Contents of KTI (r = 1.00;p < 0.05) and BBI (r = 0.89;p < 0.05) as well as BBI monomeric (r = 0.89;p < 0.05) and polymeric forms (r = 0.95;p < 0.05) in okara and in soybean were strongly correlated. Low urease index activity indicated that okara was heated adequately to inactivate antinutritional factors. The proximate composition of raw okara, advantageous rTIA, and a very low EV (2.74-3.78 kJ/g) qualify this byproduct for potential application in food preparation as a functional ingredient in dietary products.

Composition of proteins in okara as a byproduct in hydrothermal processing of soy milk.

Protein quality, based on its subunit composition, in okara obtained as a byproduct during hydrothermal cooking of soy milk was assessed. The composition of 7S and 11S protein fractions was correlated with the physicochemical properties of protein in okara produced from six soybean varieties. The basic 7S globulin (Bg7S) and 11S protein were two main proteins in okara. Investigated soybean genotypes produced okara with mainly acidic A(5) and basic B(1,2,4) polypeptides of 11S proteins. Soybean 11S content was not an indicator of okara protein recovery or extractability. Of all tested relationships, extractable soluble protein content of okara was influenced only by soybean Bg7S (r = 0.86; p < 0.05) and its light subunit contents (r = 0.93; p < 0.05). Okara protein recovery depended on Bg7S heavy subunit content in soybeans (r = 0.81; p < 0.05). The high quantity of vegetable protein in okara (around 35%) and very high protein extractability (around 85%) qualify this byproduct for potential application in food preparation as a functional ingredient.

Assessment of soy genotype and processing method on quality of soybean tofu.

Protein quality in six soybean varieties, based on subunit composition of their protein, was correlated with quality of the produced tofu. Also, protein changes due to a pilot plant processing method involving high temperature/pressure and commercial rennet as coagulant were assessed. In each soybean variety, glycinin (11S) and ß-conglycinin (7S) as well as 11S/7S ratio significantly changed from beans to tofu. Between varieties, the 11S/7S protein ratio in seed indicated genotypic influence on tofu yield and gel hardness (r = 0.91 and r = 0.99, respectively; p < 0.05). Also, the 11S/7S ratio correlated with soymilk pH (r = 0.89, p < 0.05), leading to a relationship between soymilk pH with protein recovery and yield of tofu (r = 0.94 and r = 0.91, respectively; p < 0.05). The soybean ß'-subunit of 7S protein negatively influenced tofu hardness (r = -0.91, p < 0.05). Seed protein composition and proportion of 7S protein subunits under the applied production method had an important role in defining tofu quality.

Profile and functional properties of seed proteins from six pea (Pisum sativum) genotypes.

Extractability, extractable protein compositions, technological-functional properties of pea (Pisum sativum) proteins from six genotypes grown in Serbia were investigated. Also, the relationship between these characteristics was presented. Investigated genotypes showed significant differences in storage protein content, composition and extractability. The ratio of vicilin:legumin concentrations, as well as the ratio of vicilin + convicilin: Legumin concentrations were positively correlated with extractability. Our data suggest that the higher level of vicilin and/or a lower level of legumin have a positive influence on protein extractability. The emulsion activity index (EAI) was strongly and positively correlated with the solubility, while no significant correlation was found between emulsion stability (ESI) and solubility, nor between foaming properties and solubility. No association was evident between ESI and EAI. A moderate positive correlation between emulsion stability and foam capacity was observed. Proteins from the investigated genotypes expressed significantly different emulsifying properties and foam capacity at different pH values, whereas low foam stability was detected. It appears that genotype has considerable influence on content, composition and technological-functional properties of pea bean proteins. This fact can be very useful for food scientists in efforts to improve the quality of peas and pea protein products.