The characteristics of soybean protein isolate obtained by synergistic modification of high hydrostatic pressure and phospholipids as a promising replacement of milk in ice cream

The properties of the rice resistant starch processing and its application in skimmed yogurt

Extrusion is typically employed to prepare resistant starch (RS). However, the process is complicated. In this study, the effects of twin-screw extrusion on the crystallinity, thermal properties, and functional properties of starch formed in different extrusion zones were investigated. The effects of this process on the rheological properties and microstructure of RS-added skimmed yogurt were also studied. According to the results, the RS content increased from 7.40 % in the raw material to 33.79 % in the extrudate. The A-type crystal structure of the starch was not observed. The dissociation temperature of the extruded starch ranged from 87.76 °C to 100.94 °C. The glycemic index (GI) of skimmed yogurt fortified with 0.4 % RS was 48.7, and the viscosity was also improved. The microstructure exhibited a uniform network of the starch-protein structure. The findings may serve as a theoretical basis for the application of RS in the food industry.

Evaluation of sono-physico-chemical and processing effects in the mixed sarcoplasmic protein/soy protein isolate system

Since it may be employed to guide the production of high-quality plant protein as a partial substitute for animal protein using sono-physico-chemical effects, it is important to investigate the mixing of animal and plant protein in ultrasound (UID)-assisted processing systems. A study group of sono-physico-chemical processing with five distinct soy protein isolate (SPI)/ sarcoplasmic protein (SPN) ratios was developed in this work. The results showed that adding additional SPN to the mixed protein can increase its sono-physico-chemical impact, and this effect is greatest when the ratio of SPI to SPN is 1:3. The high SPN group's grafting rate rose from 39.13% to 55.26% in comparison to the high SPI content group. Quercetin (Que) may more readily modify SPN than SPI in the "dual protein" system used in this work, highlighting the critical function of plant protein in controlling the effects of UID-assisted processing in the "dual protein" system. Changes in apparent viscosity and microstructure are the primary parameters that affect the severity of sono-physico-chemical effects in SPI/SPN mixed protein systems, in addition to structural variables.

Effects of high pressure synergistic enzymatic physical state and concentration on the denaturation of polyphenol oxidase

The synergistic effect of the initial state of the enzyme and pressure level on the denaturation of PPO has not been clear yet, but it significantly affects the application of high hydrostatic pressure (HHP) in the enzyme-containing food processing. Solid (S-) and low/high concentration liquid (LL-/HL-) polyphenol oxidase (PPO) was used as the study object, and the microscopic conformation, molecular morphology and macroscopic activity of PPO under HHP treatments (100-400 MPa, 25 °C/30 min) were investigated by spectroscopic techniques. The results show that the initial state has a significant effect on the activity, structure, active force and substrate channel of PPO under pressure. The effec can be ranked as follows: physical state > concentration > pressure, S-PPO > LL-PPO > HL-PPO. High concentration has a weakening effect on the pressure denaturation of the PPO solution. Under high pressure, the α-helix and concentration factors play a crucial role in stabilizing the structure.

Study on the Structure, Function, and Interface Characteristics of Soybean Protein Isolate by Industrial Phosphorylation

The impacts of industrial phosphorylation on the structural changes, microstructure, functional, and rheological features of soybean protein isolate (SPI) were spotlighted. The findings implied that the spatial structure and functional features of the SPI changed significantly after treatment with the two phosphates. Sodium hexametaphosphate (SHMP) promoted aggregation of SPI with a larger particle size; sodium tripolyphosphate (STP) modified SPI with smaller particle size. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) results showed insignificant alterations in the structure of SPI subunits. Fourier transform infrared (FTIR) and endogenous fluorescence noted a decline in α-helix quantity, an amplification in β-fold quantity, and an increase in protein stretching and disorder, indicating that phosphorylation treatment fluctuated the spatial structure of the SPI. Functional characterization studies showed that the solubility and emulsion properties of the SPI increased to varying degrees after phosphorylation, with a maximum solubility of 94.64% for SHMP-SPI and 97.09% for STP-SPI. Emulsifying activity index (EAI) and emulsifying steadiness index (ESI) results for STP-SPI were better than those for SHMP-SPI. Rheological results showed that the modulus of G' and G″ increased and the emulsion exhibited significant elastic behavior. This affords a theoretical core for expanding the industrial production applications of soybean isolates in the food and various industries.

Functional Properties of Brewer's Spent Grain Protein Isolate: The Missing Piece in the Plant Protein Portfolio

Plant protein sources, as a part of developing sustainable food systems, are currently of interest globally. Brewer's spent grain (BSG) is the most plentiful by-product of the brewing industry, representing ~85% of the total side streams produced. Although nutritionally dense, there are very few methods of upcycling these materials. High in protein, BSG can serve as an ideal raw material for protein isolate production. This study details the nutritional and functional characteristics of BSG protein isolate, EverPro, and compares these with the technological performance of the current gold standard plant protein isolates, pea and soy. The compositional characteristics are determined, including amino acid analysis, protein solubility, and protein profile among others. Related physical properties are determined, including foaming characteristics, emulsifying properties, zeta potential, surface hydrophobicity, and rheological properties. Regarding nutrition, EverPro meets or exceeds the requirement of each essential amino acid per g protein, with the exception of lysine, while pea and soy are deficient in methionine and cysteine. EverPro has a similar protein content to the pea and soy isolates, but far exceeds them in terms of protein solubility, with a protein solubility of ~100% compared to 22% and 52% for pea and soy isolates, respectively. This increased solubility, in turn, affects other functional properties; EverPro displays the highest foaming capacity and exhibits low sedimentation activity, while also possessing minimal gelation properties and low emulsion stabilising activity when compared to pea and soy isolates. This study outlines the functional and nutritional properties of EverPro, a brewer's spent grain protein, in comparison to commercial plant protein isolates, indicating the potential for the inclusion of new, sustainable plant-based protein sources in human nutrition, in particular dairy alternative applications.

Effect of Different Polymerization Degrees and Fatty Acids of Polyglycerol Esters on the Physical Properties and Whippability of Recombined Dairy Cream

Polyglycerol esters (PGEs) are used as emulsifiers in recombined dairy cream (RDC) to improve product quality. In this study, the effects of four PGEs with different polymerization degrees and esterification on the particle size, viscosity, zeta potential, and microrheology of RDC emulsions were investigated, and the whipping time, overrun, serum loss, and firmness of the RDC emulsions were recorded. The results show that the addition of the PGEs reduced the particle size (from 2.75 μm to 1.48-1.73 μm) and increased the viscosity (from 41.92 cP to 73.50-100 cP) and stability (from 0.354 to 0.105-0.128), which were related to the change in interfacial properties and the weakening of Brownian motion, but there were differences in the effect on the whipping behavior of the RDCs. Although the addition of 0.9% triglyceride monolaurate gave the emulsion the best stability, the RDC had a longer whipping time (318 s) and a lower overrun (116.6%). Comparatively, the 0.7-0.9% concentrations of PGE55 and tripolycerol monostearate (TMS) provided RDC with good stability and aeration characteristics, allowing inflation within 100 s and expansion rates of up to 218.24% and 186.88%, respectively. In addition, the higher degree of polymerization of polyglyceryl-10 monstearate (PMS) did not work well at any concentration. These results contribute to understanding the mechanism of action of PGEs and improving the quality of RDC.

Separation and purification of antioxidant peptides from purple speckled kidney bean by macroporous adsorption resin and analysis of amino acid composition

The protein hydrolysate of purple speckled kidney bean (PSKB) was used as the raw material in this study, and the antioxidant peptide of the PSKB protein hydrolysate was purified using macroporous resin. The XAD-7HP macroporous resin was selected as the best purification material, and the static adsorption-desorption of the purified PSKB antioxidant peptide was optimized. The optimum static adsorption and desorption conditions were as follows: the adsorption capacity reached 11.93 ± 0.11 mg/ml at pH 7 for 24 h, and the desorption capacity was 5.24 ± 0.04 mg/ml with 60% ethanol for 30 min. Under this condition, the amount of antioxidant peptide obtained by adsorption-desorption was the highest. The optimum process conditions were as follows: the appropriate flow rate was 1 ml/min, and the optimal injection volume was 40 ml. The adsorption amount at this time can reach 12.19 ± 0.15 mg/ml. The components with an elution time of 10-30 min were separated using the reversed-phase high-performance liquid chromatography (RP-HPLC) technique to obtain three main components, namely, RP₁, RP₂, and RP₃. The DPPH free radical scavenging ability reached 56.26 ± 0.56, 66.42 ± 0.56, and 78.57 ± 0.56%, respectively, which were 36.65, 46.34 ± 0.56, and 54.39 ± 0.56% higher than those before purification. The amino acid sequences of the three components were identified as Phe-Leu-Val-Asp-Arg-Ile, Phe-Leu-Val-Ala-Pro-Asp-Asp, and Lys-Asp-Arg-Val-Ile-Ser-Glu-Leu.