Enzymatic Hydrolysis and Fermentation of Pea Protein Isolate and Its Effects on Antigenic Proteins, Functional Properties, and Sensory Profile

Combinations of enzymatic hydrolysis using different proteolytic enzymes (papain, Esperase®, trypsin) and lactic fermentation with Lactobacillus plantarum were used to alter potential pea allergens, the functional properties and sensory profile of pea protein isolate (PPI). The order in which the treatments were performed had a major impact on the changes in the properties of the pea protein isolate; the highest changes were seen with the combination of fermentation followed by enzymatic hydrolysis. SDS-PAGE, gel filtration, and ELISA results showed changes in the protein molecular weight and a reduced immunogenicity of treated samples. Treated samples showed significantly increased protein solubility at pH 4.5 (31.19–66.55%) and at pH 7.0 (47.37–74.95%), compared to the untreated PPI (6.98% and 40.26%, respectively). The foaming capacity was significantly increased (1190–2575%) compared to the untreated PPI (840%). The treated PPI showed reduced pea characteristic off-flavors, where only the treatment with Esperase® significantly increased the bitterness. The results from this study suggest that the combination of enzymatic hydrolysis and lactic fermentation is a promising method to be used in the food industry to produce pea protein ingredients with higher functionality and a highly neutral taste. A reduced detection signal of polyclonal rabbit anti-pea-antibodies against the processed protein preparations in ELISA furthermore might indicate a decreased immunological reaction after consumption.

DSResSol: A Sequence-Based Solubility Predictor Created with Dilated Squeeze Excitation Residual Networks

Protein solubility is an important thermodynamic parameter that is critical for the characterization of a protein’s function, and a key determinant for the production yield of a protein in both the research setting and within industrial (e.g., pharmaceutical) applications. Experimental approaches to predict protein solubility are costly, time-consuming, and frequently offer only low success rates. To reduce cost and expedite the development of therapeutic and industrially relevant proteins, a highly accurate computational tool for predicting protein solubility from protein sequence is sought. While a number of in silico prediction tools exist, they suffer from relatively low prediction accuracy, bias toward the soluble proteins, and limited applicability for various classes of proteins. In this study, we developed a novel deep learning sequence-based solubility predictor, DSResSol, that takes advantage of the integration of squeeze excitation residual networks with dilated convolutional neural networks and outperforms all existing protein solubility prediction models. This model captures the frequently occurring amino acid k-mers and their local and global interactions and highlights the importance of identifying long-range interaction information between amino acid k-mers to achieve improved accuracy, using only protein sequence as input. DSResSol outperforms all available sequence-based solubility predictors by at least 5% in terms of accuracy when evaluated by two different independent test sets. Compared to existing predictors, DSResSol not only reduces prediction bias for insoluble proteins but also predicts soluble proteins within the test sets with an accuracy that is at least 13% higher than existing models. We derive the key amino acids, dipeptides, and tripeptides contributing to protein solubility, identifying glutamic acid and serine as critical amino acids for protein solubility prediction. Overall, DSResSol can be used for the fast, reliable, and inexpensive prediction of a protein’s solubility to guide experimental design.

Review: current trends in oat protein recovery and utilization in aqueous food systems

Oat protein itself, as a substance, has extensively been studied providing information on its nutritional value, some functional properties and possible applicability in food systems. Chosen protein isolation methods and technological aspects define final composition of obtained oat protein product, its concentration, nutrition value and its functionality in food industry. Scientific data on oat protein recovery methods, typically relying on protein solubility or dry fractionation, provides an insufficient knowledge about the success in commercialization of oat protein recovery technologies and their derivatives in form of oat protein. The aim of the study was to analyse and summarize the research findings on oat protein extraction methods and functional properties of oat protein. Semi-systematic, monographic methods were used to analyse the oat protein isolation techniques, functional properties of oat protein in aqueous food systems, covering the latest information on oat protein extraction methods. Wet and dry isolation methods were demonstrated as main methods in oat protein extraction. Functional properties of oat protein, such as thermal stability, solubility, emulsification, water hydration capacity and foaming were reviewed and evaluated, identifying limitations and protein alterations which occur through the oat protein extraction process. The study provides recent trends in oat protein recovery technologies, along with an overview of current and potential oat protein utilization in food systems.

A3D Database: Structure-based Protein Aggregation Predictions for the Human Proteome

Motivation: Protein aggregation is associated with highly debilitating human disorders and constitutes a major bottleneck for producing therapeutic proteins. Our knowledge of the human protein structures repertoire has dramatically increased with the recent development of the AlphaFold (AF) deep-learning method. This structural information can be used to understand better protein aggregation properties and the rational design of protein solubility. This article uses the Aggrescan3D (A3D) tool to compute the structure-based aggregation predictions for the human proteome and make the predictions available in a database form. Results: Here, we present the A3D Database, in which we analyze the AF-predicted human protein structures (for over 17 thousand non-membrane proteins) in terms of their aggregation properties using the A3D tool. Each entry of the A3D Database provides a detailed analysis of the structure-based aggregation propensity computed with A3D. The A3D Database implements simple but useful graphical tools for visualizing and interpreting protein structure datasets. We discuss case studies illustrating how the database could be used to analyze physiologically relevant proteins. Furthermore, the database enables testing the influence of user-selected mutations on protein solubility and stability, all integrated into a user-friendly interface. Availability and implementation: A3D Database is freely available at: http://biocomp.chem.uw.edu.pl/A3D2/hproteome

Extraction, Characterization and Utilization of Fish Protein Concentrate

Progress in investigation for extraction of fish protein concentrate (FPC) by different solvents (acetone, isopropyl alcohol and hexane: ethanol azeotropic mixture as Canadian, British and Indian method) of pink perch (Nemipterus spp.) analyzed for their functional properties and further utilized in developing value added product. FPC extracted by isopropyl alcohol was superior with significantly (P<0.05) highest protein, lowest moisture and fat content. Significantly (P<0.05) superior viscosity (118.37 cP), Protein solubility (84.40%), Emulsification capacity (68.53%), Emulsification stability (60.92%), Foaming capacity (140.01%), Foaming stability (121.70%) and Water holding capacity (25.35 mL/g) for isopropyl alcohol compared with other solvents. Due to typical fishy odor fish meat replaced with FPC (0, 5, 10, 15 and 20 %) in fish finger formulation with FPC incorporation at 10% levels were most acceptable. Strong linearity (R2) for changes biochemical values (R2>0.96) and microbiological values (R2=0.9705) were found. Sensory evaluation had a negative correlation (R2>0.814) during storage suggesting shelf life of 11 days. Suggesting utilization of low value fishes for extraction of high quality proteins and their application for development of novel foods.

Physicochemical properties of frozen tuna fish as affected by immersion ohmic thawing and conventional thawing

One of the key points in the frozen food processing is thawing with minimal damage to the quality. Since the commonly used methods for thawing of foods are slow and reduce the quality of the product, application of an efficient method seems necessary. In this research, thawing of tuna fish was performed by immersion ohmic method. Thawing rate roles a vital key in the quality and significantly increased by ohmic ([Formula: see text], the mean of ohmic group) in comparison with conventional thawing ([Formula: see text], the mean of conventional group) methods. Immersion ohmic thawing increased rate of thawing about 5 times. Parameters important in quality such as T-VBN, protein solubility, thawing evaporation loss, pH, thawing loss and press juice were measured. Group analyses showed significant difference between ohmic and conventional treatment in protein solubility, thawing evaporation and thawing loss (p < 0.05).

Antioxidant activity of protein hydrolysate from snakehead fish (Channa striata) viscera obtained by enzymatic process

Snakehead fish (Channa striata) in South Sumatra, Indonesia has been widely used as a raw material in the processing of typical Palembang food industry, namely pempek, kemplang, and kerupuk. During its processing, not all parts of the fish can be utilized. In general, only 40% of the fish is used for consumption and 60% is wasted as by-products. One of the by-product produced during processing is viscera which can still be used as value-added products. One alternative is to use viscera as raw material in the production of fish protein hydrolysate (FPH) which is well known to have functional properties such as antioxidant, antibacterial, antihypertensive, and anticancer. This research was aim to determine the antioxidant activity of FPH made from snakehead fish viscera as a source of natural antioxidants. The research was conducted by papain treatments with the concentration of enzymes used were 1%, 2% and 3%. Evaluation of the hydrolysis process was done by measure the soluble protein and DH (degree of hydrolysis) while antioxidant activity was carried out by DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2-Azinobis 3-ethyl benzothiazoline6-sulfonic acid) assay. DH of fish protein hydrolysate was found to be 68.79%, 77.06% and 72.63%, respectively while protein solubility gave values of 5.69%, 6.15% and 6.56% respectively. The highest antioxidant activity was attained at enzyme concentration of 3% with DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2-Azinobis 3-ethyl benzothiazoline 6-sulphonic acid) value were 37.26% and 58.58% respectively.

Effect of Heat Treatment on Rumen Degradability of Gliricia sepium leaves

An experiment with the objective to investigate the effect of different temperature regimes during heat treatment of Gliricidia sepium leaves was conducted following a completely randomized design with 4 treatments and 3 replications. Gliricidia leaves were exposed to three temperature regimes namely oven heating at 60oC (T60), 90oC (T90), and 120oC (T120) respectively and followed by sun-drying compared to sun drying as control (Con). The dry matter and protein degradation were measured using In Sacco method in three fistulated Bali cows fed a standard diet. Protein solubility (a) and the insoluble but potentially degradable fraction (b) were linearly reduced (P<0,001) by the increased temperature in the oven as compared to sun drying. The degradation rate (c) of protein in the rumen was increased at all heating treatments. The effective dry matter and protein degradation of gliricidia leaf was significantly (P<0,01) reduced by heat treatment in T90 and no further reduction in T120. The solubility fraction of DM was significantly reduced (P<0.05) when heated in the oven at 120oC, meanwhile the b value for DM linearly decline with the increasing heating temperature. Heating also increased the lag time required for the degradation to commence. It, therefore, can be concluded that oven drying at 90oC is a simple effective means to reduce ruminal protein degradation of gliricidia leaves.

Extruded soybean in pig feeding in the nursery phase:performance

The objective of this study was to evaluate the replacement of soybean meal by extruded whole soybean in the feeding of pigs in the nursery phase. Thirty-six piglets (Landrace x Large White), with 45 days weighing on average 11.36 kg, distributed in arandomized block design, three treatments, six replicates, two animals per repetition were used. The treatments consisted of: control treatment (T1) basal diet, basal diet with 10% replacement of soybean meal by extruded soybean (T2), basal diet with 20% replacement of soybean meal by extruded soybean (T3). The variables analyzed were: average weight, feed intake, weight gain and feed conversion. The levels of ureatic activity, ether extract, crude protein, protein solubility and volatile moisture of extruded soybean were verified. No difference was found (P>0.05) between the inclusion levels of extruded soybean in piglet diets in the nursery phase for the variables studied. The processing of extruded whole soybean did not affect its digestibility. Extrudedsoybeans at a level of up to 20% included in piglet feeding during the nursery phase can be a possible substitute for soybean meal, without compromising the performance of the animals.