Changes in Hydrophobic Interactions among Gluten Proteins during Dough Formation

Delicate Analysis of Interacting Proteins and Their Assemblies by Flow Field-Flow Fractionation Techniques

We study the efficiency of several asymmetrical flow field-flow fractionation (AF4) techniques to investigate self-associating wheat gluten proteins. We compare the use of a denaturing buffer including sodium dodecyl sulfate (SDS) and a mild chaotropic solvent, water/ethanol, as the eluent, on a model gluten sample. Through a thorough analysis of the data obtained from coupled light scattering detectors and with the identification of molecular composition of the eluted protein, we evidence coelution events in several conditions. We show that the focus step used in conventional AF4 with the SDS buffer leads to the formation of aggregates that coelute with monomeric proteins. By contrast, a frit-inlet device enables the fractionation of individual wheat proteins in the SDS buffer. Interestingly conventional AF4, using water/ethanol as eluent, is an effective method for fractionating gluten proteins and their complex dynamic assemblies, which involve weak forces and are composed of both monomeric and polymeric proteins.

Underutilised palm stearin as hard stock for deep-frying medium and its performance for oil uptake in instant noodles

BACKGROUND

As a by-product of the palm oil industry, palm stearin is often overlooked despite having several beneficial properties, such as excellent stability, which is critically essential to meet the demand of the global food trend in producing safer processed food. Specifically, deep frying of food is often associated with the production of toxic compounds that could potentially migrate into the food system when oils are degraded under continuous heating. The incorporation of palm stearin is regarded as a cost-effective and efficient method to modify the fatty acid composition of oils, enhance the frying qualities and lower the degradation rate.

RESULTS

This study blended 5% and 10% palm stearin into palm oil to investigate the deep-frying performance and impact on food quality. Increasing the palm stearin content improved the frying oil's oxidative and hydrolytic stability, evidenced by reduction of total polar material, free fatty acid and total oxidation value. Addition of palm stearin increased the slip melting point which improved the oil's oxidative stability but no significant increase in oil content of instant noodles was observed. Scanning electron microscopy and fluorescence microscopy showed the formation of larger pores in the noodle structure that facilitated oil retention.

CONCLUSION

Blending palm stearin into frying oil enhanced the frying stability and minimally affected the oil uptake in instant noodles. This article presents the viability of blending palm stearin into frying oils to develop longer-lasting frying oils. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Use of hydration properties of proteins to understand their functionality and tailor texture of extruded plant-based meat analogues

Different protein sources create distinct textures in plant-based meat due to differences in their hydration properties when exposed to different time, temperature, and shear regimes, which in turn depend upon their solubility, protein structure, and specific amino acids. This research aimed to identify these differences and manipulate them to reach a desired texture utilizing simple and reproducible analytical methods to characterize protein properties as either cold or heat swelling. Protein functionality was determined through least gelation concentration (LGC), water absorption index (WAI), and rapid visco analysis (RVA). Cold swelling or CS proteins (pea protein isolate, soy protein isolate, Arcon S soy protein concentrate) were characterized by an LGC < 14% and/ or WAI > 4.0 g/g, while LGC > 16% and/ or WAI < 4.0 g/g indicates proteins with heat swelling or HS properties (Arcon F soy protein concentrate, wheat gluten, and fava protein concentrate). An RVA peak time of around or less than 3 min (<75°C peak temperature) indicated CS properties while greater than 3.5 min (>80°C peak temperature) was considered HS. Protein mixes or treatments comprising mainly of different combinations and ratios of CS proteins were hypothesized to create a softer textured vegetable protein product or texturized vegetable protein (TVP) and those based on HS proteins a firmer TVP. Bulk density was higher for HS treatments (274-287 g/L) than for CS treatments (160-223 g/L). CS treatments exhibited a microstructure that was porous, while HS showed a dense, laminar microstructure. Texture profile analysis showed that CS treatments seemed to show a lower hardness (1154-1595 g) than the HS treatments (1893-2231 g). PRACTICAL APPLICATION: Controlling texture can be a valuable tool when producing a plant-based meat product. Different applications have various texture requirements. For example, a plant-based fish stick would require a softer texture than a hamburger or chicken nugget. By increasing the knowledge of how protein functionality affects meat analogue texture, the time needed to produce new products with novel textures can be reduced. Money could also be saved by being able to quickly replace ingredients with a more affordable or accessible protein with similar swelling abilities to preserve product quality.

Unravelling the nutritional and health benefits of wheat bread enriched with meat powder from laying hen fed diet with insect (Hermetia illucens) meal

Wheat bread is among stable foods that are nutritionally imbalanced, thus enrichment is crucial. We evaluated the nutritional impact of high-valued wheat bread enriched with varying levels of meat powder from hen fed diet with insect (Hermetia illucens)-based meal. Crude protein and ash in bread increased with increasing inclusion of meat powder. Limiting amino acids like lysine and threonine in enriched bread products increased by 3.0-4.5 and 1.8-3.1-folds, respectively. Omega 3 fatty acids were significantly enhanced in bread fortified with meat powder. Vitamins (retinol, nicotinic acid, and pantothenic acid) were significantly increased in supplemented bread products. Iron, zinc, and calcium increased by 1.1, 1.2 and 3.0-folds in enriched bread with 30% meat powder. Colour, flavour and overall acceptability of breads prepared with 25 and 30% meat powder were highly ranked. Our findings demonstrate that meat powder (i.e., from hen fed insect-based diets) enrichment would provide added health and nutritional benefits to bread products without having adverse effects on any functional or sensory properties. Thus, this could be a novel strategy and trend for improving bread products, that might generate increasing demand for a healthier consumer-oriented lifestyle.

A chromatographic and immunoprofiling approach to optimising workflows for extraction of gluten proteins from flour

Ingestion of gluten proteins from wheat, and related prolamin proteins from barley, rye, and oats, can cause adverse reactions in individuals with coeliac disease and IgE-mediated allergies. As there is currently no cure for these conditions, patients must practice avoidance of gluten-containing foods. In order to support patients in making safe food choices, foods making a "gluten-free" claim must contain no more than 20 mg/Kg of gluten. Mass spectrometry methods have the potential to provide an alternative method for confirmatory analysis of gluten that is complementary to analysis currently undertaken by immunoassay. As part of the development of such methodology the effectiveness of two different extraction procedures was investigated using wholemeal wheat flour before and after defatting with water-saturated butan-1-ol. A single step extraction with 50 % (v/v) propan-2-ol containing 2 M urea and reducing agent (buffer 1) was compared with a two-step extraction using 60 % (v/v) aqueous ethanol (buffer 2) followed by re-extraction of the pellet using buffer 1, using either wheel mixing under ambient conditions (19 °C) or sonication at 60 °C. The procedures were compared based on total protein extraction efficiency and the composition of the extracts determined using a combination of HPLC, SDS-PAGE and immunoblotting with a panel of four gluten-specific monoclonal antibodies. Defatting generally had a detrimental effect on extraction efficiency and sonication at 60 °C only improved extraction efficiency with buffer 2. Although the single-step and two-step procedures were equally effective at extracting protein from the samples, analysis of extracts showed that the two-step method gave a more complete extraction of gluten proteins. Future studies will compare the effectiveness of these procedures when applied in the sample workflows for mass spectrometry based methods for determination of gluten in food.

Processing and Properties Analysis of Grain Foods

Foods from grains and grain-derived ingredients are among the most important energy and nutrient source for humans [...]

Delineating the dynamic transformation of gluten morphological distribution, structure, and aggregation behavior in noodle dough induced by mixing and resting

To understand the formation of gluten network and its regulation on noodle qualities upon mixing and resting, the dynamic distribution and molecular transformation of gluten were tracked and quantified. Confocal laser scanning microscopy and scanning electron microscopy images showed that appropriate mixing (8 min) and resting (60 min) induced a compact gluten network with higher gluten junctions. Both height and width of protein molecular chains were increased by hydration during mixing and reduced after excessive resting (90 min). According to the size exclusion/reversed phase-HPLC profiles, mixing induced slight depolymerization of large glutenin polymer, and α-gliadin subunits were more susceptible to polymerization after appropriate mixing and resting. Increased mixing time was accompanied by the strengthening of ionic and hydrogen bonds, and the weakening of hydrophobic interaction. PCA and correlation analysis revealed the accurate regulation of mixing and resting induced dynamic distribution and evolution of gluten on the macroscopic noodle qualities.