Wheat Bran Proteins: A Review of Their Uses and Potential

In situ fortification of cereal by-products with vitamin B12: An eco-sustainable approach for food fortification

Vitamin B12 deficiency poses significant health risks, especially among populations with limited access to animal-based foods. This study explores the utilisation of cereal bran by-products, wheat (WB) and oat bran (OB), as substrates for in situ vitamin B12 fortification through solid-state fermentation (SSF) using Propionibacterium freudenreichii. The impact of various precursors addition, including riboflavin, cobalt, nicotinamide and DMBI on vitamin B12 production, along with changes in microbial growth, chemical profiles, and vitamin B12 yields during fermentation was evaluated. Results showed that WB and OB possess favourable constituents for microbial growth and vitamin B12 synthesis. The substrates supplemented with riboflavin, cobalt, and DMBI demonstrated enhanced B12 production. In addition, pH levels are essential in microbial viability and cobalamin biosynthesis. Monosaccharides and organic acids play a crucial role, with maltose showing a strong positive association with B12 production in OB, while in WB, citric acid exhibits significant correlations with various factors.

Smart proteins as a new paradigm for meeting dietary protein sufficiency of India: a critical review on the safety and sustainability of different protein sources

India, a global leader in agriculture, faces sustainability challenges in feeding its population. Although primarily a vegetarian population, the consumption of animal derived proteins has tremendously increased in recent years. Excessive dependency on animal proteins is not environmentally sustainable, necessitating the identification of alternative smart proteins. Smart proteins are environmentally benign and mimic the properties of animal proteins (dairy, egg and meat) and are derived from plant proteins, microbial fermentation, insects and cell culture meat (CCM) processes. This review critically evaluates the technological, safety, and sustainability challenges involved in production of smart proteins and their consumer acceptance from Indian context. Under current circumstances, plant-based proteins are most favorable; however, limited land availability and impending climate change makes them unsustainable in the long run. CCM is unaffordable with high input costs limiting its commercialization in near future. Microbial-derived proteins could be the most sustainable option for future owing to higher productivity and ability to grow on low-cost substrates. A circular economy approach integrating agri-horti waste valorization and C1 substrate synthesis with microbial biomass production offer economic viability. Considering the use of novel additives and processing techniques, evaluation of safety, allergenicity, and bioavailability of smart protein products is necessary before large-scale adoption.

Structurally manipulated antioxidant peptides derived from wheat bran: Preparation and identification

Bioactive peptide's development is facing two challenges in terms of its lower yield and limited understanding of structurally orientated functionality. Therefore, peptides were prepared from wheat bran via a cocktail enzyme for achieving a higher level of hydrophobic amino acids than traditional method. The obtained peptides exhibited great antioxidant activities against H2O2-induced oxidative stress in HepG2 cells. Among them, 91 bioactive peptides were selected through the virtual screening, and their N-terminal and C-terminal contained many hydrophobic amino acids. Then the peptides with capacity to interact with Keap1 were identified by in silico simulation, because Keap1 acts as a sensor of redox insults. The results revealed that peptides DLDW and DLGL demonstrated the highest binding affinities, and a bridge was formed between Asp of DLGL and Arg415 of Klech domain, contributing to interfering Keap1-Nrf2 interaction. These findings implied a potential application of wheat bran peptides as nutraceuticals and health-promoting ingredients.

Larval nutritional-stress and tolerance to extreme temperatures in the peach fruit fly, Bactrocera zonata (Diptera: Tephritidae)

Within the factors affecting insect tolerance to extreme environmental conditions, insect nutrition, particularly of immature stages, has received insufficient attention. In the present study, we address this gap by investigating the effects of larval nutrition on heat and cold tolerance of adult Bactrocera zonata - an invasive, polyphagous fruit fly pest. We manipulated the nutritional content in the larval diet by varying the amount of added yeast (2-10% by weight), while maintaining a constant sucrose content. Adults derived from the different larval diets were tested for their tolerance to extreme heat and cold stress. Restricting the amount of yeast reduced the efficacy of the larval diet (i.e. number of pupae produced per g of diet) as well as pupal and adult fresh weight, both being significantly lower for yeast-poor diets. Additionally, yeast restriction during the larval stage (2% yeast diet) significantly reduced the amount of protein but not lipid reserves of newly emerged males and females. Adults maintained after emergence on granulated sugar and water for 10 days were significantly more tolerant to extreme heat (i.e. knock-down time at 42 ^oC) when reared as larvae on yeast-rich diets (8% and 10% yeast) compared to counterparts developing on a diet containing 2% yeast. Nevertheless, the composition of the larval diet did not significantly affect adult survival following acute cold stress (exposure to -3°C for 2 hrs.). These results are corroborated by previous findings on Drosophilid flies. Possible mechanisms leading to nutrition-based heat-tolerance in flies are discussed.

Derivation of Kokumi γ-Glutamyl Peptides and Volatile Aroma Compounds from Fermented Cereal Processing By-Products for Reducing Bitterness of Plant-Based Ingredients

Current food production methods and consumption behaviours are unsustainable and contribute to environmental harm. One example is food waste-around 38% of food produced is wasted each year. Here, we show that two common food waste products, wheat bran and brewer's spent grain, can successfully be upcycled via miso fermentation. During the fermentation process, kokumi γ-glutamyl peptides, known to increase mouthfulness, are produced; these include γ-ECG (oxidized), γ-EVG, γ-EV, γ-EE, γ-EF, and γ-EL. The profiles of kokumi peptides and volatile aroma compounds are correlated with koji substrate, pH, and enzymatic activity, offering straightforward parameters that can be manipulated to increase the abundance of kokumi peptides during the fermentation process. Correlation analysis demonstrates that some volatile aroma compounds, such as fatty acid ethyl esters, are correlated with kokumi peptide abundance and may be responsible for fatty, greasy, and buttery aromas. Consumer sensory analysis conveys that the bitter taste of vegetables, such as that in endives, can be dampened when miso extract containing kokumi peptides is added. This suggests that kokumi peptides, along with aroma volatile compounds, can enhance the overall flavour of plant-based products. This study opens new opportunities for cereal processing by-product upcycling via fermentation, ultimately having the potential to promote a plant-based diet.

Physiochemical and Sensory Properties of Bread Fortified with Wheat Bran and Whey Protein Isolates

This study investigated the effect of fortifying baked goods with wheat bran (WBPI) and whey protein isolates (WPI) on their physicochemical and sensory properties. The aim was to enhance the nutritional value by incorporating high-protein ingredients. WBPI and WPI, which are rich in essential amino acids, were chosen to create high-protein flour blends. The main advantage of WBPI is that it is derived from readily available and inexpensive wheat bran. High-protein flour blends fortified with substitutions of 5%, 10%, and 15% flour with WBPI and WPI were subjected to chemical and rheological analysis. WBPI substitution slightly increased water binding and softening, but it resulted in a decrease in dough quality. In contrast, WPI substitution prolonged dough development time, improved dough stability, and enhanced farinographic quality. WBPI-substituted dough exhibited comparable extensographic properties to the reference flour, with 5% WBPI substitution leading to improved energy and dough resistance. However, as the level of WBPI flour substitution increased, extensographic parameters gradually declined without further enhancing the dough's mechanical properties. Samples with 5% WPI substitution demonstrated superior mechanical properties compared to the reference sample. Baguette with high WBPI substitution was associated with reduced overall acceptance due to a bitter taste caused by the presence of small peptides, ferulic acid, and tannins, as confirmed by correlation analysis.

Cereal bran proteins: recent advances in extraction, properties, and applications

The projected global population is expected to reach around 9.7 billion by 2050, indicating a greater demand for proteins in the human diet. Cereal bran proteins (CBPs) have been identified as high-quality proteins, with potential applications in both the food and pharmaceutical industries. In 2020, global cereal grain production was 2.1 billion metric tonnes, including wheat, rice, corn, millet, barley, and oats. Cereal bran, obtained through milling, made up 10-20% of total cereal grain production, varying by grain type and milling degree. In this article, the molecular composition and nutritional value of CBPs are summarized, and recent advances in their extraction and purification are discussed. The functional properties of CBPs are then reviewed, including their solubility, binding, emulsifying, foaming, gelling, and thermal properties. Finally, current challenges to the application of CBPs in foods are highlighted, such as the presence of antinutritional factors, low digestibility, and allergenicity, as well as potential strategies to improve the nutritional and functional properties by overcoming these challenges. CBPs exhibit nutritional and functional attributes that are similar to those of other widely used plant-based protein sources. Thus, CBPs have considerable potential for use as ingredients in food, pharmaceutical, and other products.

Valorization of wastes and by-products of nuts, seeds, cereals and legumes processing

Wastes and by-products of nuts, seeds, cereals and legumes carry a unique potential for valorization into value-added ingredients due to their protein, dietary fiber, antioxidant, vitamin and mineral contents. The most crucial factor in the recovery of value-added ingredients and bioactives from the wastes and by-products is the utilization of the most efficient extraction technique. This work is an overview of the classification of wastes and by-products of nuts, seeds, cereals and legumes processing, the methods used in the extraction of valuable compounds such as proteins, dietary fibers, phenolics, flavonoids and other bioactives. This chapter provides insights on the promising applications of extracted ingredients in various end products. A special emphasis is given to the challenges and improvement methods for extraction of value-added compounds from wastes and by-products of nuts, seeds, cereals and legumes processing.

Valorization of Food Waste to Produce Value-Added Products Based on Its Bioactive Compounds

The rapid growth of the global population and changes in lifestyle have led to a significant increase in food waste from various industrial, agricultural, and household sources. Nearly one-third of the food produced annually is wasted, resulting in severe resource depletion. Food waste contains rich organic matter, which, if not managed properly, can pose a serious threat to the environment and human health, making the proper disposal of food waste an urgent global issue. However, various types of food waste, such as waste from fruit, vegetables, grains, and other food production and processing, contain important bioactive compounds, such as polyphenols, dietary fiber, proteins, lipids, vitamins, organic acids, and minerals, some of which are found in greater quantities in the discarded parts than in the parts accepted by the market. These bioactive compounds offer the potential to convert food waste into value-added products, and fields including nutritional foods, bioplastics, bioenergy, biosurfactants, biofertilizers, and single cell proteins have welcomed food waste as a novel source. This review reveals the latest insights into the various sources of food waste and the potential of utilizing bioactive compounds to convert it into value-added products, thus enhancing people’s confidence in better utilizing and managing food waste.

Wheat bran layers: composition, structure, fractionation, and potential uses in foods

Wheat bran, the main by-product of dry milling of wheat, is currently mainly used in the animal feed industry, but has attracted attention as a food ingredient owing to its high dietary fiber and phytochemical contents, providing excellent physiological effects. The bran layers (aleurone layer, outer pericarp and intermediate layer) contain different compositions, structures, and nutrients, and have different properties. Each layer, when separated and isolated, potentially could find more extensive applications in foods. This triggered interest in isolating the bran layers using milling and wet- or dry-fractionation techniques based on their chemical or physical properties. The recent progress has allowed the production of commercial products from wheat bran layers, particularly aleurone-rich products, enhancing the value of wheat bran layers and their applications in food. The present review highlights the recent advances in studying the chemical composition including distribution of chemical components, physical structure, biopolymer matrix, and physicochemical properties of each wheat bran layer. Technologies to fractionate wheat bran layers and utilization of different bran layers in foods are discussed and reviewed, providing new strategies for improving the value of wheat bran and utilization of wheat bran in foods.

Isolation, characterization, and utilization of wheat bran protein fraction for food application

Wheat bran (WB), a low-cost industrial by-product, is a vital source of high-quality proteins, minerals, vitamins, and several bioactive compounds. The present study encompasses the identification of appropriate bran streams of a commercial roller flour mill (CRFM) essentially based on hector liter weight, (HLW), optimization of WB protein isolation process, amino acid characterization, rendering more emphasis on simple water-soluble albumins, having higher commercial viability, and its application in food formulation. Total WB protein was 16.18% protein, the sum of the extracted proteins viz. albumin (2.43%), a prolamin (2.47%), glutelin (5.25%), globulin (1.92%), and insoluble proteins (4.09%) was 12.08%. Following albumin extraction, residual WB was subjected to ultra-sonication which further increased albumin protein yield from 2.43 to 3.07%. The extracted WB albumin isolate (WBAI) was utilized to develop high protein bread having significantly high volume and protein content, compared to control bread. The structural and sensorial attributes of the developed bread were superior compared to control bread. Thus, WBAI has a tremendous scope as a natural, affordable potential inexpensive food improver/fortificant to address protein-energy malnutrition (PEM). The process has the great advantage of being eco-friendly, besides, residual bran can still be used as cattle feed, enhancing profitability and viability.

Climate-Changed Wheat: The Effect of Smaller Kernels on the Nutritional Value of Wheat

Through plant breeding and improved agronomy, the average wheat kernel size increased globally by about 40% from 1940 to 2000. Millers demand larger kernels because they contain more white flour (endosperm). Climate pressures are resulting in frequently reduced kernel size and routine rejection by the commodity system. If whole-wheat flour instead of white flour is the target, these smaller kernels have unrealized value. A total of 94% of Americans do not meet the recommended fiber intake, and inadequate fiber intake plays a role in the development of multiple chronic diseases. A total of 98% of the fiber in wheat is found in the bran. Bran content was measured in “big” (x¯ = 0.042 g/kernel) and “small” (x¯ = 0.023 g/kernel) kernels in nine varieties over locations and years. On average, small kernels contained 15.9% more bran than big kernels (n = 54, p < 0.001) and, thus, had higher mineral and fiber content. In the majority of cases, baking showed no difference in whole-wheat quality among flours within the same variety, regardless of kernel size, based on bread slice height and surface area. Wheat that was rejected by commercial mills as too small produced satisfactory bread. Favoring larger kernels and white flour production has unintended health consequences. Valuing smaller kernels and whole-wheat production provides an outlet for farmers dealing with increasing climate pressures and leads to an end-use product which can improve human health by increasing dietary fiber consumption.

The compliance of nutrition claims on pita bread in Lebanon and risk on public health: a cross-sectional study

Background

Mislabeling is a type of fraud, that can lead to major health concerns, especially when used on staple foods like bread. This study aimed to assess the compliance of nutrition claims on pre-packaged Pita bread in Mount Lebanon with national (LIBNOR; NL 661:2017) and international (CODEX; CAC/GL -2–1985) standards.

Methods

A cross-sectional study was conducted and Lebanese bread samples (n = 75) were collected from all the registered bakeries in Mount Lebanon directorate (n = 25). The claim compliance assessment was based on values of the nutrition facts panel and standard nutrient analyses, following official methods.

Results

Of all assessed breads, 84% carried nutrition claims, and 25.3% carried health claims. Among nutrition claims, 70.7% had non-addition claims, 56.0% had nutrient content claims, and 1.3% had comparative claims. The results showed a high prevalence of nutrition claims with majority non-compliant. Based on the nutrition facts panel, only 32.4% of the sugar related claims, 45.5% of the fiber claims, and 54.4% of salt claims were eligible to make those statements. Based on the chemical nutrient analyses, only 47.0% of sugar claims, 16.1% of fiber claims, and 37.5% of salt claims were compliant. All the claims related to protein (n = 7) were compliant.

Conclusions

These results suggest the urgent need to develop clear guidelines for the effective implementation of the current standard; in order to prevent mislead consumers from making poor decisions at the point-of-sale, which might affect their overall health and efforts towards proper nutrition.

In vitro digestion characteristics of cereal protein concentrates as assessed using a pepsin-pancreatin digestion model

An alkaline extraction method has been used in many studies to extract total protein from cereal samples. Wheat bran protein concentrate (WBPC), oat bran protein concentrate (OBPC), and barley protein concentrate (BPC) were prepared by alkaline extraction and isoelectric precipitation to study their functional and nutritional properties. The three protein concentrates were hydrolysed by an in vitro pepsin-pancreatin digestion model. Their digestibility (%) and degree of hydrolysis (DH%) were evaluated, and SDS-PAGE electrophoresis was used to illustrate the protein and peptides patterns. The change of the particle sizes and the release of the essential amino acids was followed during the digestion process. The in vitro digestibility of WBPC, OBPC and BPC was 87.4%, 96.1% and 76.9%, respectively. The DH% of protein concentrates were between 50 and 60%. The change of the particle size distribution values Dv(50) was assumed to be related to protein aggregations during the digestion. The protein fractions were identified and the degradation during the digestion and were analysed by SDS-PAGE; the gels of WBPC and OBPC digestion showed virtually complete degradation whereas the intensive bands of undigested protein were presented for BPC. The generation of the free amino acids and short chain peptides were significantly higher at the end of the intestinal digestion compared to the stages of before and after gastric digestion. Higher content of the deficient amino acids such as lysine and threonine were found comparing to the level of deficient amino acids in cereal grains but does not meet the daily recommended intake.

Towards Functional Insect Feeds: Agri-Food By-Products Enriched with Post-Distillation Residues of Medicinal Aromatic Plants in Tenebrio molitor (Coleoptera: Tenebrionidae) Breeding

Sustainability, circular economy and alternative production systems are urgent imperatives for humanity and animal husbandry. Unless wasted, agri-food by-products can offer a promising source of high value. We evaluated the effect of rice bran (RB), corncob (CC), potato peels (PP), solid biogas residues (BR), and olive-oil processing residuals (OR), as alternative substrates to wheat bran (WB as control), on the growth and nutritional value of Tenebrio molitor during its breeding for animal feeds and/or human consumption. Innovation-wise, we further investigated the substrate supplementation (0, 10, 20%) with post-distillation residues of Mediterranean aromatic-medicinal plants (MAPs: lavender, Greek oregano, rosemary, olive; 1:1:1:1 ratio). Tenebrio molitor larvae (TML) were reared in all the studied substrates, and TML and diets’ proximate and fatty acid compositions as well as total phenol and flavonoid content and antioxidant potential were assessed using standard procedures. After statistical analysis of correlations, we observed that CC promoted oviposition and progeny survival; larval weight and dry matter were positively affected mainly by dietary energy and fat content; number of TML and/or larval weight increased using 10% MAPs inclusion in WB, RB and OR or RB, OR, BR and PP, respectively, which did not affect protein content; TML fatty acid composition decreased the content of saturated ones and increased that of mono-unsaturated ones; MAPs residues had an apparent favorable impact on total phenolic content and antioxidant activity of each substrate, with RB displaying the highest capacity and content. These findings indicate that alternative substrates can be exploited and their enrichment with natural phenolics is able to influence T. molitor growth, offering highly beneficial and nutritional value.

Valorisation of wheat bran to produce natural pigments using selected microorganisms

Pigments are compounds with highly diverse structures and wide uses, which production is increasing worldwide. An eco-friendly method of bioproduction is to use the ability of some microorganisms to ferment on renewable carbon sources. Wheat bran (WB) is a cheap and abundant lignocellulosic co-product of low recalcitrance to biological conversion. Microbial candidates with theoretical ability to degrade WB were first preselected using specific databases. The microorganisms were Ashbya gossypii (producing riboflavin), Chitinophaga pinensis (producing flexirubin), Chromobacterium vaccinii (violacein) and Gordonia alkanivorans (carotenoids). Growth was shown for each on minimal salt medium supplemented with WB at 5 g.L^-1. Activities of the main enzymes consuming WB were measured, showing leucine amino-peptidase (up to 8.45 IU. mL^-1) and β-glucosidase activities (none to 6.44 IU. mL^-1). This was coupled to a FTIR (Fourier Transform Infra-Red) study of the WB residues that showed main degradation of the WB protein fraction for C. pinensis, C. vaccinii and G. alkanivorans. Production of the pigments on WB was assessed for all the strains except Ashbya, with values of production reaching up to 1.47 mg.L^-1. The polyphasic approach used in this study led to a proof of concept of pigment production from WB as a cheap carbon source.

A Structured Approach to Recover Valuable Compounds from Agri-food Side Streams

Food side streams contain useful compounds such as proteins, sugars, polyphenols, and amino acids that might get discarded during processing. The concentration of these components may be low (e.g., fruit side streams are mainly composed by water, around 90%, while polyphenol content in rapeseed meal is less than 3% dry weight) and therefore effective separation techniques should be evaluated. The aim of this review is to identify the different process steps (like pretreatment, volume reduction, phase change, solid removal, purification, and formulation) required to recover high-value products from agri-food residues. It reviews different plant-based byproducts as sources (cereal bran, fruit pomace, oilseed meals, fruit wastewater) of valuable compounds and discusses the relevant technologies required for processing (such as extraction, adsorption, crystallization, drying, among others). A structured approach to design recovery processes presented focused on high purity products. This work demonstrates that multiple high-value products can be recovered from a single agri-food side stream depending on the processing steps and the origin source (strong and soft structures and wastewater).

Wheat bran, as the resource of dietary fiber: a review

Wheat bran is a major by-product of white flour milling and had been produced in large quantities around the world; it is rich in dietary fiber and had already been used in many products such as whole grain baking or high dietary fiber addition. It has been confirmed that a sufficient intake of dietary fiber in wheat bran with appropriate physiological functions is beneficial to human health. Wheat bran had been considered as the addition with a large potential for improving the nutritional condition of the human body based on the dietary fiber supplement. The present review summarized the available information on wheat bran related to its dietary fiber functions, which may be helpful for further development of wheat bran as dietary fiber resource.

Impact of wheat bran micronization on dough properties and bread quality: Part I - Bran functionality and dough properties

This study aimed to investigate the effect of wheat bran micronization on its functionality including physicochemical and antioxidant properties, and dough properties. Coarse bran (D₅₀ = 362.3 ± 20.5 μm) was superfine ground to medium (D₅₀ = 60.4 ± 10.1 μm) and superfine (D₅₀ = 11.3 ± 2.6 μm) bran, accompanied with increasing specific surface area and breakdown of aleurone layers. Bran micronization increased its soluble dietary fibre content, ferulic acid liberation, and antioxidant properties including total polyphenol content, ABTS•+ and DPPH• scavenging activities, while decreased its water retention capacity and insoluble dietary fibre content. Moreover, bran micronization impacted dough rheological properties. The dough with superfine bran had higher water absorption and gelatinization temperature, peak viscosity, final viscosity and setback value, lower stability time, resistance to extension, and extensibility than the dough with coarse bran. This dough furthermore exhibited more solid-like properties characterized by decreased loss moduli and frequency dependence (n').

Antimicrobial, Antioxidant, Sensory Properties, and Emotions Induced for the Consumers of Nutraceutical Beverages Developed from Technological Functionalised Food Industry By-Products

This study aims to develop nutraceutical beverages containing food processing by-products in their formulation, and determine the opinion of consumers. This is done by testing whether they know that the main ingredients of the product are by-products, performing an overall acceptability test of the developed beverages, and evaluating the emotions induced by the newly developed beverages for consumers. The main ingredients used for the preparation of added-value beverages were fermented milk permeate (containing galactooligosaccharides), extruded and fermented wheat bran (WB) (containing ≥6.0 log₁₀ CFU g⁻¹ viable antimicrobial properties showing lactic acid bacteria (LAB) strains), and different fruit/berry by-products (FBB) (as a source of compounds showing antioxidant properties). The definition of the quantities of bioactive ingredients was based on the overall acceptability of the prepared beverages, as well as on emotions induced in consumers by the tested beverages. Functional properties of the developed beverages were proofed by the evaluation of their antimicrobial and antioxidant properties, as well as viable LAB count during storage. Desirable changes in extruded and fermented WB were obtained: Fermentation reduced sugar concentration and pH in samples with predominant lactic acid isomer L(+). In addition, the viable LAB count in the substrate was higher than 6.0 log₁₀ CFU g⁻¹, and no enterobacteria remained. By comparing the overall acceptability of the beverages enriched with WB, the highest overall acceptability was shown for the samples prepared with 10 g of the extruded and fermented WB (7.9 points). FBB showed desirable antimicrobial activity: Shepherd inhibited—2, sea buckthorn—3, blueberries—5, and raspberries—7 pathogens from the 10 tested. Comparing different beverage groups prepared with different types of FBB, in most cases (except sea buckthorn), by increasing FBB content the beverages overall acceptability was increased, and the highest score (on average, 9.5 points) was obtained for the samples prepared with 5.0 and 7.5 g of blueberries FBB. Moreover, a very strong positive correlation (r = 0.8525) was found between overall acceptability and emotion “happy” induced in consumers by the prepared beverages enriched with extruded and fermented WB and FBB. By comparing the samples prepared with the addition of WB with samples prepared with WB and FBB, it was observed that most FBB increased total phenolic compounds (TPC) content (on average, by 9.0%), except in the case of samples prepared with sea buckthorn. A very high positive correlation (r = 0.9919) was established between TPC and antioxidant activity. Finally, it can be stated that the newly developed nutraceutical beverages were acceptable for consumers, induced positive emotions, and possessed desirable antimicrobial and antioxidant properties, while being prepared in a sustainable and environmentally friendly manner.

Plant-Based Food By-Products: Prospects for Valorisation in Functional Bread Development

The industrial and small-scale processing of plant-based food materials is associated with by-products that may have a negative impact on the environment but could add value to bread-based products. The bioactivity of plant-based food by-products, their impact on the properties of functional bread, and their bioavailability/bioaccessibility leading to potential health effects when consumed was reviewed. Plant-based food by-products which may be added to bread include rice bran, wheat bran, corn bran, grape pomace/seed extract, tomato seed/skin, and artichoke stems/leaves. These by-products contain high concentrations of bioactive compounds, including phenolics, bioactive peptides, and arabinoxylan. Pre-treatment procedures, including fermentation and thermal processing, impact the properties of plant-based by-products. In most cases, bread formulated with flour from plant-based by-products demonstrated increased fibre and bioactive compound contents. In terms of the sensory and nutritional acceptability of bread, formulations with an average of 5% flour from plant-based by-products produced bread with acceptable sensory properties. Bread enriched with plant-based by-products demonstrated enhanced bioavailability and bioaccessibility and favourable bioactive properties in human blood, although long-term studies are warranted. There is a need to investigate the bioactive properties of other underutilised plant-based by-products and their potential application in bread as a sustainable approach towards improving food and nutrition security.

Fortification of durum wheat spaghetti and common wheat bread with wheat bran protein concentrate-impacts on nutrition and technological properties

Plant industrial by-products have generally low value but can be a good source of nutritional compounds. Wheat bran is the main by-product of wheat milling and contains >15% high-quality proteins. Extraction of wheat bran proteins (WBPC) and inclusion in spaghetti and bread formulations was studied to determine if the nutritional properties of these foods could be enhanced without deleterious effects on quality. Semolina was substituted with WBPC at 0, 1, 5, 10 and 20% (w/w) and made into spaghetti and a commercial bread flour was substituted with WBPC at 0, 1, 5 and 10% w/w and made into bread. Both spaghetti protein content (12.3 to 23.4%) and total essential amino acids (3.76 to 7.59%) increased with added WBPC. Overall spaghetti quality was acceptable up to 10%WBPC and superior to wholemeal, especially in appearance. However, the bread formulation used was very sensitive to WBPC especially above 1% addition.

Effect of thermal stabilization on physico-chemical parameters and functional properties of wheat bran

The food industry also focuses on the use of by-products from food processing. Wheat bran is a valuable by-product of the wheat milling process, which is rich in dietary fiber. In addition to nutritional value, dietary fiber has a functional potential in the production of novel foods. Pre-treatment of the dietary fiber using different methods can change its functional properties. The objective of this study was to evaluate the effect of stabilization process on physico-chemical parameters and functional properties of wheat bran. Wheat bran from two wheat variety was treated using microwave and hot air heating. It was observed that wheat bran included more than 45% of total dietary fiber. Results suggested that treatment of bran using both method increased total dietary fiber content. Thermal treatment process decreased the anti-nutritional agent in bran samples. Phytic acid content diminishing of 44% and 49% was observed in microwave treated bran samples. Moreover, treatment of bran using a hot air heating improved the hydration properties (water holding, water retention and swelling capacity), while oil holding capacity was not significantly altered. Treatment decreased the antioxidant activity of treated bran samples. It was observed that thermal treatment modified the color parameters of bran (lightness, yellowness and hue angle decreased and redness and Chroma increased).

Colonies of the fungus Aspergillus niger are highly differentiated to adapt to local carbon source variation

Saprobic fungi, such as Aspergillus niger, grow as colonies consisting of a network of branching and fusing hyphae that are often considered to be relatively uniform entities in which nutrients can freely move through the hyphae. In nature, different parts of a colony are often exposed to different nutrients. We have investigated, using a multi-omics approach, adaptation of A. niger colonies to spatially separated and compositionally different plant biomass substrates. This demonstrated a high level of intra-colony differentiation, which closely matched the locally available substrate. The part of the colony exposed to pectin-rich sugar beet pulp and to xylan-rich wheat bran showed high pectinolytic and high xylanolytic transcript and protein levels respectively. This study therefore exemplifies the high ability of fungal colonies to differentiate and adapt to local conditions, ensuring efficient use of the available nutrients, rather than maintaining a uniform physiology throughout the colony.

Sesame bran as an unexploited by-product: Effect of enzyme and ultrasound-assisted extraction on the recovery of protein and antioxidant compounds

Significant amount of bran is discarded from sesame processing plants and yet it is seen as waste or animal feed. This study for the first time designed to recover protein and antioxidant compounds from sesame bran. In this respect, effectiveness of four different techniques i.e. viscozyme L, alcalase, ultrasound and ultrasound-assisted enzymatic extractions were tested and compared with standard alkaline method. RSM was used to investigate the effects of extraction parameters and to determine optimum process conditions. All of the independent parameters (enzyme concentrations, pH, ultrasound power, temperature and time) had significant effects on all of the responses. Alcalase exhibited higher recovery efficiency than viscozyme L. The highest protein yield, total phenolic compound and antioxidant capacities were found in ultrasound-assisted enzymatic extraction at 836 W ultrasound power, 43 °C, 98 min, 9.8 pH value and 1.248 AU/100 g enzyme concentration. SDS-PAGE and SEM analyses were also carried out to compare extraction techniques.

The modification of the ketogenic diet mitigates its stunting effects in rodents

The high-fat and low-carbohydrate ketogenic diet (HFKD) is extensively studied within the fields of numerous diseases, including cancer and neurological disorders. Since most studies incorporate animal models, ensuring the quality of ketogenic rodent diets is important, both in the context of laboratory animal welfare as well as for the accuracy of the obtained results. In this study we implemented a modification to a commonly used ketogenic rodent chow by replacing non-resorbable cellulose with wheat bran. We assessed the effects of month-long treatment with either the unmodified or the modified HFKD on the growth and development of young male rats. Daily body weight, functional performance, and brain morphometric parameters were assessed to evaluate the influence of both applied diets on rodent development. Our results revealed that the unmodified ketogenic chow induced strong side effects that included weakness, emaciation, and brain undergrowth concomitant to growth inhibition. However, application of the ketogenic chow supplemented with wheat bran suppressed these adverse side effects, which was associated with the restoration of insulin-like growth factor 1 and a decrease in corticosterone levels. We have also shown that the advantageous results of the modified HFKD are not species- or sex-specific. Our data indicate that the proposed HFKD modification even allows for its application in young animals, without causing detrimental side effects.

Side Streams of Plant Food Processing As a Source of Valuable Compounds: Selected Examples

Industrial processing of plant-derived raw materials generates enormous amounts of by-products. On one hand, these by-products constitute a serious disposal issue because they often emerge seasonally and are prone to microbial decay. On the other hand, they are an abundant source of valuable compounds, in particular secondary plant metabolites and cell wall materials, which may be recovered and used to functionalize foods and replace synthetic additives with ingredients of natural origin. This review covers 150 references and presents select studies performed between 2001 and 2016 on the recovery, characterization, and application of valuable constituents from grape pomace, apple pomace, potato peels, tomato pomace, carrot pomace, onion peels, by-products of citrus, mango, banana, and pineapple processing, side streams of olive oil production, and cereal by-products. The criteria used were economic importance, amounts generated, relevance of side streams as a source of valuable compounds, and reviews already published. Despite a plethora of studies carried out on the utilization of side streams, relatively few processes have yet found industrial application.