Mixed legume systems of pea protein and unrefined lentil fraction: Textural properties and microstructure

A review of the effects of physical processing techniques on the characteristics of legume starches and their application in low-glycemic index foods

Physical processing techniques significantly influence the characteristics of legume starch, consequently affecting the potential applications of legume-based products. This review comprehensively examines the impact of various physical processing techniques on legume starch properties, including structure, granule morphology, gelatinization, pasting properties, solubility, and in vitro digestibility. Furthermore, it evaluates the implications of these processing methods for utilizing legumes in developing low-glycemic index (GI) foods. Notably, certain physical processing methods, such as heat-moisture treatment, ultrahigh-pressure processing, dry heat treatment, and gamma irradiation, under specific conditions, enhance the resistant starch or slowly digestible starch fractions in legume starches. This enhancement is particularly advantageous for producing low-GI foods. Conversely, techniques like annealing, extrusion, ultrasound, and germination increase starch digestibility, which is less favorable for low-GI food applications. This review also provides an up-to-date overview of the use of diverse preprocessed legume products in low-GI food production. The novelty of this review lies in its detailed comparative analysis of physical processing methods and their specific effects on legume starch digestibility, which has not been extensively covered in existing literature. The comprehensive insights presented herein will benefit the legume industry by informing effective strategies for converting legume starch into valuable low-GI products.

Heat-Induced Gelation of Chickpea and Faba Bean Flour Ingredients

This study aimed to investigate the gelling behavior of faba bean (FB) and chickpea (CP) flour between 10 and 20% (w/w) concentration at pH 3.0, 5.0, and 7.0. Both sources formed at pH 3.0 and 5.0 self-standing gels with 12% (w/w) of flour, while 16% (w/w) of flour was required to obtain a gel at pH 7.0. During gelling between 40 and 70 °C, a sharp increase of the elastic modulus G' was observed in both flours, mainly due to water absorption and swelling of the starch, one of the major constituents in the ingredients. Increasing the temperature at 95 °C, G' increased due to the denaturation of globulins and therefore the exposure of their internal part, which allowed more hydrophobic interactions and the formation of the gel. After cooling, both FB and CP gels displayed a solid-like behavior (tan δ ranging between 0.11 and 0.18) with G' values at pH 3.0 and 5.0 significantly (p < 0.05) higher than those at pH 7.0, due to the lower electrostatic repulsions at pHs far from the isoelectric point. The rheological properties were supported by the water binding capacity values, confirming the better gels' strength described by rheological analysis. These results will enhance our understanding of the role of legume flours in formulating innovative and sustainable food products as alternatives to animal ones.

Electrical Fields in the Processing of Protein-Based Foods

Electric field-based technologies offer interesting perspectives which include controlled heat dissipation (via the ohmic heating effect) and the influence of electrical variables (e.g., electroporation). These factors collectively provide an opportunity to modify the functional and technological properties of numerous food proteins, including ones from emergent plant- and microbial-based sources. Currently, numerous scientific studies are underway, contributing to the emerging body of knowledge about the effects on protein properties. In this review, "Electric Field Processing" acknowledges the broader range of technologies that fall under the umbrella of using the direct passage of electrical current in food material, giving particular focus to the ones that are industrially implemented. The structural and biological effects of electric field processing (thermal and non-thermal) on protein fractions from various sources will be addressed. For a more comprehensive contextualization of the significance of these effects, both conventional and alternative protein sources, along with their respective ingredients, will be introduced initially.

Novel Protein Sources for Applications in Meat-Alternative Products—Insight and Challenges

Many people are increasingly interested in a vegetarian or vegan diet. Looking at the research and the available options in the market, there are two generations of products based on typical proteins, such as soy or gluten, and newer generation proteins, such as peas or faba beans, or even proteins based on previously used feed proteins. In the review, we present the characteristics of several proteins that can be consumed as alternatives to first-generation proteins used in vegan foods. In the following part of the work, we describe the research in which novel protein sources were used in terms of the product they are used for. The paper describes protein sources such as cereal proteins, oilseeds proteins coming from the cakes after oil pressing, and novel sources such as algae, insects, and fungus for use in meat analog products. Technological processes that can make non-animal proteins similar to meat are also discussed, as well as the challenges faced by technologists working in the field of vegan products.

Providing Stability to High Internal Phase Emulsion Gels Using Brewery Industry By-Products as Stabilizers

The modern brewing industry generates high amounts of solid wastes containing biopolymers-proteins and polysaccharides-with interesting technological and functional properties. The novelty of this study was to use raw by-product from the brewing industry in the development of high internal phase emulsion (HIPE) gels. Thus, the influence of the emulsion's aqueous phase pH and the by-product's concentration on structural and physical stability of the emulsions was studied. The microstructure was analyzed using cryo-field emission scanning electron microscopy. To evaluate the rheological behavior, oscillatory tests (amplitude and frequency) and flow curves were conducted. Moreover, the physical stability of the emulsions and the color were also studied. The increase in by-product concentration and the pH of the aqueous phase allowed development of HIPE gels with homogeneously distributed oil droplets of regular size and polyhedral structure. The data from the rheology tests showed a more stable structure at higher pH and higher by-product concentration. This study widens the possibilities of valorizing the brewing industry's by-products as stabilizers when designing emulsions.

Effect of pH and Pea Protein: Xanthan Gum Ratio on Emulsions with High Oil Content and High Internal Phase Emulsion Formation

Electrostatic interaction between protein and polysaccharides could influence structured liquid oil stability when emulsification is used for this purpose. The objective of this work was to structure sunflower oil forming emulsions and High Internal Phase Emulsions (HIPEs) using pea protein (PP) and xanthan gum (XG) as a stabilizer, promoting or not their electrostatic attraction. The 60/40 oil-in-water emulsions were made varying the pH (3, 5, and 7) and PP:XG ratio (4:1, 8:1, and 12:1). To form HIPEs, samples were oven-dried and homogenized. The higher the pH, the smaller the droplet size (Emulsions: 15.60-43.96 µm and HIPEs: 8.74-20.38 µm) and the oil release after 9 weeks of storage at 5 °C and 25 °C (oil loss < 8%). All systems had weak gel-like behavior, however, the values of viscoelastic properties (G' and G″) increased with the increment of PP:XG ratio. Stable emulsions were obtained at pHs 5 and 7 in all PP:XG ratios, and at pH 3 in the ratio 4:1. Stable HIPEs were obtained at pH 7 in the ratios PP:XG 4:1, 8:1, and 12:1, and at pH 5 at PP:XG ratio 4:1. All these systems presented different characteristics that could be exploited for their application as fat substitutes.