Valorization of cereal by-product hemicelluloses: Fractionation and purity considerations

Enhancing the dispersibility of Gelidium amansii-derived microfibrillated cellulose through centrifugal fractionation

Hydrothermal pretreatment is useful for microfibrillated cellulose (MFC) preparation due to its safety, but the remaining hemicellulose might affect MFC properties. This study aimed to investigate the effect of centrifugation time on hemicellulose removal and the physicochemical properties of MFC obtained after hydrothermal pretreatment and micro-fibrillation. In this study, centrifugation was applied to the MFC suspension at varying duration times. Composition analysis and Fourier transform infrared spectra indicated that fractionated MFC has no hemicellulose content after 10, 20, and 30 min centrifugation. It also showed an approximately 5 times higher than 0.5 % g/g of initial solid concentration, indicated by a lower gel concentration point, than unfractionated MFC. Scanning electron microscope images of the fractionated MFC for 30 min (MFC2C) presented thin, long cellulose fibrils of 517 nm in average diameter and 635-10,000 nm in length that induced a slower sedimentation rate. MFC2C dispersion was also improved by autoclave sterilization by regulating cellulose structure, rheology, and crystallinity. As a result, MFC dispersibility can be enhanced by removing hemicellulose through simple centrifugation.

Valorization of Spent Grains from Beer Production through β-Glucan Extraction

Brewers' spent grains (BSG) are the major byproduct of the brewing industry. Recently, it has been found that β-glucan, which can be used as a food supplement, can be extracted from BSG and offers the greatest added value. This study aimed to investigate the effects of temperature (45-90 °C) and time (30-120 min) on β-glucan extraction efficiency when using hot water extraction. β-glucan was precipitated upon 80% ethanol addition. The chemical compositions were examined. The highest β-glucan concentration and yield were obtained at a temperature and time of 60 °C and 90 min, respectively. The functional properties of the extracted β-glucan were analyzed and compared with other commercial stabilizers such as sodium carboxymethyl cellulose (CMC), xanthan gum, gum arabic, and oat β-glucan. All stabilizers exhibited non-Newtonian flow behavior, except for gum arabic, which exhibited Newtonian flow behavior. The water holding capacity of BSG β-glucan was 6.82 g/g and the creaming index of the emulsions stabilized with BSG β-glucan was 89.05%. BSG β-glucan improved the color and stability of orange juice by reducing the precipitation of orange pulp. This study illustrated that BSG β-glucan can be used as a stabilizer and viscosity enhancer in foods, depending on the concentration, which can be applied to a variety of foods.

Ingredients, structure and reconstitution properties of instant powder foods and the potential for healthy product development: a comprehensive review

Instant foods are widely presented in powder forms across different food segments, which potentially can be formulated with functional or beneficial compounds to provide health benefits. Many reconstituted instant powder foods form colloidal suspensions with complex structures. However, designing instant powder food could be challenging due to the structural complexity and high flexibility in formulation. This review proposed a new classification method for instant powder foods according to the solubility of ingredients and the structure of the reconstituted products. Instant powder foods containing insoluble ingredients are discussed. It summarised challenges and current advances in powder treatments, reconstitution improvement, and influences on food texture and structure to facilitate product design in related industries. The characteristics and incorporation of the main ingredients and ingredients with health benefits in product development were reviewed. Different products vary significantly in the ratios of macronutrients. The macronutrients have limited solubility in water. After being reconstituted by water, the insoluble components are dispersed and swell to form colloidal dispersions with complex structures and textures. Soluble components, which dissolve in the continuous phase, may facilitate the dispersing process or influence the solution environment. The structure of reconstituted products and destabilising factors are discussed. Both particle and molecular structuring strategies have been developed to improve wettability and prevent the formation of lumps and, therefore, to improve reconstitution properties. Various types of instant food have been developed based on healthy or functional ingredients and exhibit positive effects on the prevention of non-communicable diseases and overall health. Less processed materials and by-products are often chosen to enhance the contents of dietary fibre and phenolic compounds. The enrichment of phenolic compounds, dietary fibres and/or probiotics tend to be simultaneous in plant-based products. The process of the ingredients and the formulation of products must be tailored to design the desired structure and to improve the reconstitution property.

Overview of the Sustainable Valorization of Using Waste and By-Products in Grain Processing

In an increasingly resource-constrained era, using waste and by-products from grain processing has a wide appeal. This is due to the nutritive value and economic aspects of this process and due to its compatibility with the trend towards more sustainable food systems. Following the fundamentals of circular economy, a current need is the effective utilization of grain waste and by-products for conversion into value-added products in the food industry. The aim of this study is twofold: (1) using bibliometrics and the literature found in various databases, we aim to understand the progress of valorizing grain waste and by-products in human nutrition. The literature within various databases, namely, Google Scholar, Web of Science, and Elsevier Scopus, has been evaluated for its merits and values. (2) We aim to explore knowledge-based strategies by reviewing the literature concerning the possible use of grain waste and by-products for the food processing industry, reducing the burden on virgin raw materials. The review allowed us to unlock the latest advances in upcycling side streams and waste from the grain processing industry.

Functional and Nutritional Characteristics of Natural or Modified Wheat Bran Non-Starch Polysaccharides: A Literature Review

Wheat bran (WB) consists mainly of different histological cell layers (pericarp, testa, hyaline layer and aleurone). WB contains large quantities of non-starch polysaccharides (NSP), including arabinoxylans (AX) and β-glucans. These dietary fibres have long been studied for their health effects on management and prevention of cardiovascular diseases, cholesterol, obesity, type-2 diabetes, and cancer. NSP benefits depend on their dose and molecular characteristics, including concentration, viscosity, molecular weight, and linked-polyphenols bioavailability. Given the positive health effects of WB, its incorporation in different food products is steadily increasing. However, the rheological, organoleptic and other problems associated with WB integration are numerous. Biological, physical, chemical and combined methods have been developed to optimise and modify NSP molecular characteristics. Most of these techniques aimed to potentially improve food processing, nutritional and health benefits. In this review, the physicochemical, molecular and functional properties of modified and unmodified WB are highlighted and explored. Up-to-date research findings from the clinical trials on mechanisms that WB have and their effects on health markers are critically reviewed. The review points out the lack of research using WB or purified WB fibre components in randomized, controlled clinical trials.

Carbohydrate-active enzymes in animal feed

Considering an ever-growing global population, which hit 8 billion people in the fall of 2022, it is essential to find solutions to avoid the competition between human food and animal feed for croplands. Agricultural co-products have become important components of the circular economy with their use in animal feed. Their implementation was made possible by the addition of exogenous enzymes in the diet, especially carbohydrate-active enzymes (CAZymes). In this review, we describe the diversity and versatility of microbial CAZymes targeting non-starch polysaccharides to improve the nutritional potential of diets containing cereals and protein meals. We focused our attention on cellulases, hemicellulases, pectinases which were often found to be crucial in vivo. We also highlight the performance and health benefits brought by the exogenous addition of enzymatic cocktails containing CAZymes in the diets of monogastric animals. Taking the example of the well-studied commercial cocktail Rovabio™, we discuss the evolution, constraints and future challenges faced by feed enzymes suppliers. We hope that this review will promote the use and development of enzyme solutions for industries to sustainably feed humans in the future.

Recent trends in nanocomposite packaging films utilising waste generated biopolymers: Industrial symbiosis and its implication in sustainability

Uncontrolled waste generation and management difficulties are causing chaos in the ecosystem. Although it is vital to ease environmental pressures, right now there is no such practical strategy available for the treatment or utilisation of waste material. Because the Earth's resources are limited, a long-term, sustainable, and sensible solution is necessary. Currently waste material has drawn a lot of attention as a renewable resource. Utilisation of residual biomass leftovers appears as a green and sustainable approach to lessen the waste burden on Earth while meeting the demand for bio-based goods. Several biopolymers are available from renewable waste sources that have the potential to be used in a variety of industries for a wide range of applications. Natural and synthetic biopolymers have significant advantages over petroleum-based polymers in terms of cost-effectiveness, environmental friendliness, and user-friendliness. Using waste as a raw material through industrial symbiosis should be taken into account as one of the strategies to achieve more economic and environmental value through inter-firm collaboration on the path to a near-zero waste society. This review extensively explores the different biopolymers which can be extracted from several waste material sources and that further have potential applications in food packaging industries to enhance the shelf life of perishables. This review-based study also provides key insights into the different strategies and techniques that have been developed recently to extract biopolymers from different waste byproducts and their feasibility in practical applications for the food packaging business.

Advances in extraction, purification, structural characteristics and biological activities of hemicelluloses: A review

Hemicelluloses, a major component of plant cell walls, are a non-cellulosic heteropolysaccharide composed of several distinct sugars that is second in abundance to cellulose, which are one of the most abundant and cheapest renewable resources on earth. Hemicelluloses structure is complex and its chemical structure varies greatly among the different plant species. In addition to its wide use in production of feed and other chemical materials, hemicelluloses are known for its remarkable biological activities that remain largely underutilised to date. Therefore, comprehensive investigations of hemicelluloses structural and biological properties would be helpful for achieving rational utilisation and high-value conversion of this underutilised substance into agents with enhanced health benefits for incorporation in drugs and health foods. In this review, details of diverse research initiatives that have enhanced our understanding of hemicelluloses properties are summarised, including hemicelluloses sources, extraction and purification methods, structural characteristics and biological activities. Furthermore, hemicelluloses structure-activity relationships and new directions for future hemicelluloses research studies are discussed.

Second generation Pichia pastoris strain and bioprocess designs

Yeast was the first microorganism used by mankind for biotransformation processes that laid the foundations of industrial biotechnology. In the last decade, Pichia pastoris has become the leading eukaryotic host organism for bioproduct generation. Most of the P. pastoris bioprocess operations has been relying on toxic methanol and glucose feed. In the actual bioeconomy era, for sustainable value-added bioproduct generation, non-conventional yeast P. pastoris bioprocess operations should be extended to low-cost and renewable substrates for large volume bio-based commodity productions. In this review, we evaluated the potential of P. pastoris for the establishment of circular bioeconomy due to its potential to generate industrially relevant bioproducts from renewable sources and waste streams in a cost-effective and environmentally friendly manner. Furthermore, we discussed challenges with the second generation P. pastoris platforms and propose novel insights for future perspectives. In this regard, potential of low cost substrate candidates, i.e., lignocellulosic biomass components, cereal by-products, sugar industry by-products molasses and sugarcane bagasse, high fructose syrup by-products, biodiesel industry by-product crude glycerol, kitchen waste and other agri-food industry by products were evaluated for P. pastoris cell growth promoting effects and recombinant protein production. Further metabolic pathway engineering of P. pastoris to construct renewable and low cost substrate utilization pathways was discussed. Although, second generation P. pastoris bioprocess operations for valorisation of wastes and by-products still in its infancy, rapidly emerging synthetic biology tools and metabolic engineering of P. pastoris will pave the way for more sustainable environment and bioeconomy. From environmental point of view, second generation bioprocess development is also important for waste recycling otherwise disposal of carbon-rich effluents creates environmental concerns. P. pastoris high tolerance to toxic contaminants found in lignocellulosic biomass hydrolysate and industrial waste effluent crude glycerol provides the yeast with advantages to extend its applications toward second generation P. pastoris strain design and bioprocess engineering, in the years to come.

Natural Polyphenol Recovery from Apple-, Cereal-, and Tomato-Processing By-Products and Related Health-Promoting Properties

Polyphenols of plant origin are a broad family of secondary metabolites that range from basic phenolic acids to more complex compounds such as stilbenes, flavonoids, and tannins, all of which have several phenol units in their structure. Considerable health benefits, such as having prebiotic potential and cardio-protective and weight control effects, have been linked to diets based on polyphenol-enriched foods and plant-based products, indicating the potential role of these substances in the prevention or treatment of numerous pathologies. The most representative phenolic compounds in apple pomace are phloridzin, chlorogenic acid, and epicatechin, with major health implications in diabetes, cancer, and cardiovascular and neurocognitive diseases. The cereal byproducts are rich in flavonoids (cyanidin 3-glucoside) and phenolic acids (ferulic acid), all with significant results in reducing the incidence of noncommunicable diseases. Quercetin, naringenin, and rutin are the predominant phenolic molecules in tomato by-products, having important antioxidant and antimicrobial activities. The present understanding of the functionality of polyphenols in health outcomes, specifically, noncommunicable illnesses, is summarized in this review, focusing on the applicability of this evidence in three extensive agrifood industries (apple, cereal, and tomato processing). Moreover, the reintegration of by-products into the food chain via functional food products and personalized nutrition (e.g., 3D food printing) is detailed, supporting a novel direction to be explored within the circular economy concept.

The Wheat Aleurone Layer: Optimisation of Its Benefits and Application to Bakery Products

The wheat aleurone layer is, according to millers, the main bran fraction. It is a source of nutritionally valuable compounds, such as dietary fibres, proteins, minerals and vitamins, that may exhibit health benefits. Despite these advantages, the aleurone layer is scarce on the market, probably due to issues related to its extraction. Many processes exist with some patents, but a choice must be made between the quality and quantity of the resulting product. Nonetheless, its potential has been studied mainly in bread and pasta. While the nutritional benefits of aleurone-rich flour addition to bread agree, opposite results have been obtained concerning its effects on end-product characteristics (namely loaf volume and sensory characteristics), thus ensuing different acceptability responses from consumers. However, the observed negative effects of aleurone-rich flour on bread dough could be reduced by subjecting it to pre- or post-extracting treatments meant to either reduce the particle size of the aleurone's fibres or to change the conformation of its components.

Integrated Technology for Cereal Bran Valorization: Perspectives for a Sustainable Industrial Approach

Current research focuses on improving the bioaccessibility of functional components bound to cereal bran cell walls. The main bioactive components in cereal bran that have major biological activities include phenolic acids, biopeptides, dietary fiber, and novel carbohydrates. Because of the bound form in which these bioactive compounds exist in the bran matrix, their bioaccessibility is limited. This paper aims to comprehensively analyze the functionality of an integrated technology comprising pretreatment techniques applied to bran substrate followed by fermentation bioprocesses to improve the bioaccessibility and bioavailability of the functional components. The integrated technology of specific physical, chemical, and biological pretreatments coupled with fermentation strategies applied to cereal bran previously-pretreated substrate provide a theoretical basis for the high-value utilization of cereal bran and the development of related functional foods and drugs.

In Vitro Study of the Phytochemical Composition and Antioxidant, Immunostimulant, and Hemolytic Activities of Nigella sativa (Ranunculaceae) and Lepidium sativum Seeds

The Moroccan flora abounds and is an important reserve of medicinal plants. Nigella sativa and Lepidium sativum are plants that are widely used in traditional medicine for their multiple therapeutic properties. The current study aims to highlight the biological activities that can justify and valorize the use of these plants. Flavonoids, total phenols, condensed tannins, and sugars were determined. The biological activities tested were antioxidant by determining the IC50 (defined as the concentration of an antioxidant required to decrease the initial concentration by 50%; inversely related to the antioxidant capacity), hemagglutination, and hemolytic activities. Phytochemical quantification of the seed extracts indicated that the total phenol content was largely similar for both plants and in the order of 10 mg GAE (Gallic acid equivalent)/g. On the other hand, L. sativum seeds registered a higher content of flavonoids (3.09 ± 0.04 mg QE (quercetin equivalent)/g) as compared to Nigella saliva (0.258 ± 0.058). Concerning condensed tannins, N. saliva seeds present a higher amount with a value of 7.2 ± 0.025 mg/g as compared to L. sativum (1.4 ± 0.22 mg/g). Concerning the total sugar content, L. sativum shows a higher content (67.86 ± 0.87 mg/g) as compared to N. sativa (58.17 ± 0.42 mg/g); it is also richer in mucilage with a content of 240 mg as compared to 8.2 mg for N. saliva. Examination of the antioxidant activity using a DPPH (2.2-diphenyl 1-pycrilhydrazyl) test revealed that the EButOH (n-butanol extract) and EAE (ethyl acetate extract) extracts were the most active, with IC50 values of 48.7 and 50.65 μg/mL for the N. sativa extracts and 15.7 and 52.64 μg/mL for the L. sativum extracts, respectively. The results of the hemagglutination activity of the different extracts of the two plants prepared in the PBS (phosphate-buffered saline) medium showed significant agglutination for the L. sativum extract (1/50) compared to the N. sativa extract (1/20). An evaluation of the hemolytic effect of the crude extract of the studied seeds on erythrocytes isolated from rat blood incubated in PBS buffer compared to the total hemolysis induced by distilled water showed a hemolysis rate of 54% for Nigella sativa and 34% for L. sativum. In conclusion, the two plants studied in the current work exhibited high antioxidant potential, which could explain their beneficial properties.

An Update Regarding the Bioactive Compound of Cereal By-Products: Health Benefits and Potential Applications

Cereal processing generates around 12.9% of all food waste globally. Wheat bran, wheat germ, rice bran, rice germ, corn germ, corn bran, barley bran, and brewery spent grain are just a few examples of wastes that may be exploited to recover bioactive compounds. As a result, a long-term strategy for developing novel food products and ingredients is encouraged. High-value compounds like proteins, essential amino acids, essential fatty acids, ferulic acid, and other phenols, tocopherols, or β-glucans are found in cereal by-products. This review aims to provide a critical and comprehensive overview of current knowledge regarding the bioactive compounds recovered from cereal by-products, emphasizing their functional values and potential human health benefits.

A Combination Method of Liquid Hot Water and Phosphotungstic Acid Pretreatment for Improving the Enzymatic Saccharification Efficiency of Rice Straw

Chemical pretreatment can significantly improve the enzymatic hydrolysis efficiency of lignocellulosic biomass, thereby improving the yield of sugar materials for the production of cellulosic ethanol, but commonly used acid–base catalysts are difficult to recover and reuse. In this work, a combination method of liquid hot water (LHW) and phosphotungstic acid (PTA) pretreatment was performed to improve the saccharification efficiency of rice straw, and we attempted to evaluate the reuse effect of PTA catalysts. The rice straw was first treated with LHW at 180 °C for 90 min, and then treated with 20 mM PTA at 130 °C for 60 min. After pretreatment, the cellulose hydrolysis efficiency and glucose recovery of the rice straw increased by 201.85% and 164.25%, respectively. Glucose accounted for 96.8% of the total reducing sugar in the final enzymatic hydrolysate. After each PTA pretreatment, approximately 70.8–73.2% of the PTA catalyst could be recycled. Moreover, the catalytic activity of the PTA catalyst that had been used five times did not decrease. The improved enzymatic saccharification efficiency was attributed to the removal of 89.24% hemicellulose and 21.33% lignin from the lignocellulosic substrate. The two-step LHW-PTA pretreatment could pretreat biomass in the field of cellulosic ethanol production.

Sustainable Applications for the Valorization of Cereal Processing By-Products

This review article revises the sustainable practices and applications to valorize valuable components recovered from cereal processing by-products. After introducing cereal processing by-products, their healthy compounds, and corresponding functional properties, the article explores reutilization opportunities of by-products emphasizing specific sources (e.g., oat and wheat bran, distillers' dried grains, etc.) and the biorefinery approach. Proteins and soluble dietary fibers such as arabinoxylans are of particular interest due to their content in the cereal processing by-products and their easy extraction based on conventional technologies such as enzyme-assisted extraction and membrane filtration. Non-thermal technologies have also been suggested to improve sustainability recovery approaches. Finally, the article discusses the different applications for the recovered high-added value compounds that span across biotechnology, foods, and bakery products.