Extrusion of barley and oat improves the bioaccessibility of dietary phenolic acids in growing pigs

Metabolic profiling of (poly)phenolic compounds in mouse urine following consumption of hull-less and purple-grain barley

The present study attempted for the first time to investigate the metabolic fate of (poly)phenolic compounds provided by a hull-less and purple grain barley genotype biofortified in anthocyanins. Balb/c mice were supplemented either with standard purified diet (SD) or whole-grain barley supplemented diet (WGB) for six weeks. Subsequently, (poly)phenolic metabolites were determined in urine samples by UPLC-MS/MS, and the principal metabolic pathways were elucidated. Thirty-nine (poly)phenolics compounds were identified in WGB which were distributed between the free (58%) and bound (42%) fractions, encompassing anthocyanins, phenolic acids, flavan-3-ols and flavones. Upon WGB intake, forty-two (poly)phenolic metabolites were identified, predominantly comprising phase-II sulphate, glucuronide, and/or methylated conjugates, along with colonic catabolites. Noteworthy metabolites included peonidin-3-O-glucuronide, peonidin-3-O-6''-O-malonylglucoside, and peonidin-3-O-glucoside among anthocyanins; hydroxyphenylpropanoic acid-O-sulphate among phenolic acids; and 5-(3',4'-dihydroxyphenyl)-γ-valerolactone-O-sulphate among flavan-3-ols. Metabolites like phenylpropionic, phenylacetic, hydroxybenzoic, and hippuric acids were found in both WGB and SD groups, with higher levels after barley consumption, indicating both endogenous and polyphenolic metabolism origins. Overall, this study offers valuable insights into the metabolism of (poly)phenols in purple barley, setting the stage for future investigations into the health benefits linked to the consumption of purple grain barley.

Effects of different processing techniques of palm kernel cake on processing quality of pellet feed, nutrient digestibility, and intestinal microbiota of pigs

The present study was conducted to investigate the effects of extrusion, fermentation, and enzymolysis of palm kernel cake on processing quality of pellet feed, nutrient digestibility, and intestinal microbiota of pigs. First, the pretreatment parameters of extrusion, enzymolysis, and fermentation of palm kernel cake were optimized. Then, PKC after three processing techniques were used to prepare pellet feed. A total of 160 crossbred piglets (Duroc × Landrace × Yorkshire) with an average body weight of 28 ± 0.5 kg were used in an 8-wk feeding experiment. Pigs were randomly assigned to five treatments with four replicates per treatment and eight pigs per replicates. The five experimental groups were as follows: basal diet group (whole corn-soybean meal), 10% PKC group (PKC), 10% extrusion PKC group (PPKC), 10% enzymolysis PKC group (EPKC), and 10% fermented PKC group (FPKC), respectively. At the end of the experiment, four pigs from each treatment (randomly collected one pig per pen) were sacrificed by administering a pentobarbital overdose, the gut and blood samples were collected for the quantification analysis of microbiota, hematological parameters, and apparent total tract nutrient digestibility. The results showed that all three processing techniques significantly decreased the contents of crude fiber of PKC (P < 0.01), pulverization rate (P < 0.01), powder content (P < 0.01), and increased the hardness and gelatinization starch of pellet feed (P < 0.05) compared to PKC group. In addition, PPKC significantly improved the dry matter, crude protein, and ether extract content, blood indices and average daily feed intake compared to PKC group (P < 0.01), while the parameters were similar among FPKC, EPKC, and control group (P > 0.01). Furthermore, all three processing techniques significantly increased the Lactobacillus and decreased the Escherichia levels in feces or gut compared to PKC. Collectively, extrusion, fermentation, and enzymolysis of PKC had positively enhanced the pellet quality, growth performance, nutrient digestibility, and gut microbiota, extrusion exhibited a superior feeding effect compared to fermentation and enzymolysis.

Novel processing strategies to enhance the bioaccessibility and bioavailability of functional components in wheat bran

Dietary fiber, polysaccharides and phenols are the representative functional components in wheat bran, which have important nutritional properties and pharmacological effects. However, the most functional components in wheat bran exist in bound form with low bioaccessibility. This paper reviews these functional components, analyzes modification methods, and focuses on novel solid-state fermentation (SSF) strategies in the release of functional components. Mining efficient microbial resources from traditional fermented foods, exploring the law of material exchange between cell populations, and building a stable self-regulation co-culture system are expected to strengthen the SSF process. In addition, emerging biotechnology such as synthetic biology and genome editing are used to transform the mixed fermentation system. Furthermore, combined with the emerging physical-field pretreatment coupled with SSF strategies applied to the modification of wheat bran, which provides a theoretical basis for the high-value utilization of wheat bran and the development of related functional foods and drugs.

In Vitro Digestibility and Bioaccessibility of Nutrients and Non-Nutrients Composing Extruded Brewers' Spent Grain

This study aimed to evaluate the effect of the extrusion process on the bioaccessibility of brewers’ spent grain (BSG) nutrients (carbohydrates and proteins) and non-nutrients (bioactive compounds). BSG and extruded BSG (EBSG) were digested in vitro simulating human oral-gastro-intestinal digestion and colonic fermentation. The duodenal bioaccessibility of glucose, amino acids and phenolic compounds was analyzed. The fermentability of the dietary fiber was assessed by analysis of short-chain fatty acids. Additionally, assessment of the bioaccessibility of phenolic compounds after colonic fermentation was undertaken. The antioxidant, anti-inflammatory and antidiabetic properties of the bioaccessible compounds were studied. Extrusion caused no change in the digestibility of gluten and glucose bioaccessibility (p > 0.05). Moreover, the bioaccessibility of amino acids and phenolic compounds significantly increased (p < 0.05) due to extrusion. However, higher short-chain fatty acid content was formed in colonic fermentation of BSG (p < 0.05) compared to EBSG. The latter inhibited intracellular ROS formation in IEC-6 cells and showed anti-inflammatory properties in RAW264.7 cells. With respect to antidiabetic properties, glucose absorption was lower, and the inhibition of carbohydrases higher (p < 0.05), in the presence of EBSG compared to BSG. The effects of EBSG and BSG digests on glucose transporters were not significantly different (p > 0.05). In conclusion, extrusion positively affected the nutritional value and health-promoting properties of BSG.

Effect of Flaking and Precooking Procedures on Antioxidant Potential of Selected Ancient Cereal and Legume Flours

Consumption of cereals (and particularly ancient cereals) is considered the base of a healthy diet, and all current dietary guidelines have cereals at the bottom of the nutrition pyramid. Together with cereals, legumes are an excellent source of nutrients and nutraceuticals. The effects of agroindustrial pretreatments (flaking and precooking processes) on the antioxidant potential of flours from ancient cereals and legumes were studied. The extraction of free hydrophilic phenolic compounds was carried out in a hydroalcoholic solvent mixture via an ultrasound-assisted process. Furthermore, the solid residue was successively hydrolyzed by an alkaline solution to extract the bound phenolic fraction. Both free and bound extracted fractions were then quantitatively characterized for total polyphenolic and flavonoid contents, and the antioxidant potential was determined by carrying out the ABTS and DPPH radical scavenging assays, expressing the results (in both cases) as the Trolox equivalent antioxidant capacity (TEAC/ABTS and TEAC/DPPH, respectively). The samples were also extracted in organic apolar solvents (acetone or water-saturated iso-butanol) to quantitatively characterize lipophilic antioxidant compounds and pigments. A discussion on the comparison of these analytical parameters of flours obtained from raw, flaked, and precooked cereals and legumes is reported revealing that (i) phenolic compounds are mainly present in the post-hydrolysis extract (bound fraction), (ii) the precooking process significantly reduced the concentration of antioxidants, (iii) the flaking process slightly increased the phenolic content, (iv) legumes were less influenced by pretreatments, suggesting the possibility of using legumes to enrich cereal foods.

Impact of tomato pomace powder added to extruded snacks on the in vitro gastrointestinal behaviour and stability of bioactive compounds

In this study, extruded snacks enriched with tomato pomace powder (TPP) at ratios of 5, 10, 15, and 20% (w/w) were prepared based on some preliminary experiments. The effect of tomato pomace addition to extruded snacks on the total phenolic content, total antioxidant capacity, contents of lycopene and phenolics, as well as their in vitro bioaccessibility; and additionally, physical, textural and sensory properties of the samples were investigated. According to the results, increasing levels of TPP in snacks significantly increased the content of individual phenolics including gallic acid, protocatechuic acid, 2,5-dihydroxybenzoic acid, chlorogenic acid, rutin and quercetin. Similarly, increased amount of TPP in snacks enhanced the bioaccessible protocatechuic acid, chlorogenic acid, rutin and quercetin as well as lycopene (p < 0.05). TPP incorporated snacks displayed lower expansion indices, water absorption index (WAI) and water solubility index (WSI) and lightness; but had higher hardness, redness and yellowness values than the control. However, snacks had acceptable physical and sensory properties when enriched with 10% of TPP. The results suggest that tomato pomace can be added as a functional ingredient to improve the nutritional value of snack products.

Food Processing Technologies to Develop Functional Foods With Enriched Bioactive Phenolic Compounds in Cereals

Cereal grains and products provide calories globally. The health benefits of cereals attributed to their diverse phenolic constituents have not been systematically explored. Post-harvest processing, such as drying, storing, and milling cereals, can alter the phenolic concentration and influence the antioxidant activity. Furthermore, cooking has been shown to degrade thermo-labile compounds. This review covers several methods for retaining and enhancing the phenolic content of cereals to develop functional foods. These include using bioprocesses such as germination, enzymatic, and fermentation treatments designed to enhance the phenolics in cereals. In addition, physical processes like extrusion, nixtamalization, and parboiling are discussed to improve the bioavailability of phenolics. Recent technologies utilizing ultrasound, micro- or nano-capsule polymers, and infrared utilizing processes are also evaluated for their effectiveness in improving the phenolics content and bio-accessibility. We also present contemporary products made from pigmented cereals that contain phenolics.

Enhanced Lignanamide Absorption and Antioxidative Effect of Extruded Hempseed (Cannabis sativa L.) Hull in Caco-2 Intestinal Cell Culture

Despite the latest pursuit to discover novel phenolic compounds in hempseed and its biological properties, it remains a mystery whether they can be absorbed in the human body. Extrusion treatment and extraction of the free phenolic fraction significantly (p < 0.05) improved human Caco-2 intestinal cell absorption for hempseed hull lignanamides including cannabisin B (P_app value of 1.35 × 10^-5 ± 1.0 × 10^-6) as compared to the bound fraction of raw hull (P_app value of 2.82 × 10^-6 ± 5.2 × 10^-7). Co-supplementation of the flavonoid naringenin (20 μM) further improved these absorption rates. Higher cellular antioxidant activity was observed in the free extraction fractions. Treatment with the free phenolic fraction of extruded hempseed hull (100 mg/mL) alleviated tert-butyl hydroperoxide's (25 μM) negative effects on cell viability, intracellular malondialdehyde levels, apoptosis induction, glutathione S-transferase, and glutathione levels. RNA-sequencing with the limma method unveiled a total of 2795 differentially expressed genes in 21 day-old Caco-2 intestinal cells, suggesting the changes in cell metabolism after exposure to extruded hempseed hull extract. This study could promote the utilization of extrusion technology to improve the absorption and antioxidant capacities of bioactive phenolics in plant food processing byproducts.

Recent Progress on Improving the Quality of Bran-Enriched Extruded Snacks

The incorporation of milling by-products, in particular bran, into starch-based extruded snacks allows manufacturers to address two consumer demands at once, i.e., those for goods that are more sustainably produced and of higher nutritional value. However, the higher fiber content in bran than in refined cereal flours poses a limit to the amount that can be included without compromising the quality of extruded snacks, which crucially depends on expansion. Thus, several studies have focused on the effect of bran on the physicochemical characteristics of extruded snacks, leading to the need to review the recent findings in this area. Opportunities, challenges, and potential solutions of bran-enriched snacks are addressed, and several current knowledge gaps are highlighted. Specifically, the first part of the review presents the effects of extrusion cooking on bran's compositional aspects, focusing on structural changes and product quality. After summarizing the main quality traits of extruded snacks (e.g., expansion rate, bulk density, and textural attributes), the effects of bran enrichment on the physical and sensory characteristics of the final product are discussed. Finally, bran pre-treatments as well as processing optimization are discussed as approaches to improve the quality of bran-enriched snacks.

Bioaccessibility and Bioactivity of Cereal Polyphenols: A Review

Cereal bioactive compounds, especially polyphenols, are known to possess a wide range of disease preventive properties that are attributed to their antioxidant and anti-inflammatory activity. However, due to their low plasma concentrations after oral intake, there is controversy regarding their therapeutic benefits in vivo. Within the gastrointestinal tract, some cereal polyphenols are absorbed in the small intestine, with the majority accumulating and metabolised by the colonic microbiota. Chemical and enzymatic processes occurring during gastrointestinal digestion modulate the bioactivity and bioaccessibility of phenolic compounds. The interactions between the cereal polyphenols and the intestinal epithelium allow the modulation of intestinal barrier function through antioxidant, anti-inflammatory activity and mucin production thereby improving intestinal health. The intestinal microbiota is believed to have a reciprocal interaction with polyphenols, wherein the microbiome produces bioactive and bioaccessible phenolic metabolites and the phenolic compound, in turn, modifies the microbiome composition favourably. Thus, the microbiome presents a key link between polyphenol consumption and the health benefits observed in metabolic conditions in numerous studies. This review will explore the therapeutic value of cereal polyphenols in conjunction with their bioaccessibility, impact on intestinal barrier function and interaction with the microbiome coupled with plasma anti-inflammatory effects.

Bioaccessibility of phenolic acids in Canadian hulless barley varieties

In order to gain understanding of bioaccessibility of phenolic acids in food-grade barley, an investigation was conducted using four cooked whole-grain, hulless, barley varieties. An in vitro digestion model was used to mimic human upper gastrointestinal digestion. Boiling enhanced the extractability of bound phenolic acids while digestion increased the level of free phenolic acids. The high bioaccessibilities observed were likely due to the release of bound phenolic acids during cooking and digestion. The major bioaccessible phenolics were ferulic and p-coumaric acids with bioaccessibility ranging from 131 to 173% and 51-135%, respectively. Peru-35 had significantly greater bioaccessibility of ferulic acid compared to other varieties. A hydroxycinnamic acid amide not reported before in boiled barley, N¹, N⁸- dicaffeoyl spermidine, was identified in free phenolic extracts with relatively high abundance compared to the phenolic acids. It may provide additional anti-inflammatory and antioxidant functions. These cooked whole-grain, hulless barley varieties are sources of bioaccessible phenolic acids.

Processing method modulates the effectiveness of black beans for lowering blood cholesterol in spontaneously hypertensive rats

BACKGROUND

Various foods are known to have beneficial effects on health when consumed whole; however, there is a trend towards preparing foods from processed ingredients, and it remains unclear whether the benefits of the whole food are retained. The purpose of this study was therefore to examine whether different processing techniques affect the lowering of cholesterol and the vascular effects of black beans (Phaseolus vulgaris L.).

RESULTS

Beans were prepared by overnight soaking and boiling - the standard method - and by micronization, extrusion, or dehulling and boiling, and they were then fine milled. Beans prepared by the standard method were also coarse milled. These five materials were incorporated into semi-purified diets (30% wt/wt) and fed to spontaneously hypertensive rats for 4 weeks. Body weight, blood pressure, and aorta morphology were unaltered by the diets. Fasting total cholesterol was significantly reduced in rats fed micronized beans compared with extruded beans (both fine-milled) or the bean-free diet, while boiling combined with coarse milling lowered low-density lipoprotein (LDL) cholesterol. The lack of cholesterol lowering in rats fed extruded bean compared to micronized was not explained by the amount or composition of dietary fiber or resistant starch. Differences in the polyphenolic profile as determined by high-performance liquid chromatography (HPLC) were also unable to explain the variations in cholesterol-lowering capacity.

CONCLUSION

The present study demonstrates that processing of black beans alters the health effects observed with the whole pulse, and suggests that products prepared with processed ingredients will need to be tested empirically to establish whether the biological effects are maintained in vivo. © 2020 Society of Chemical Industry.

Solutions for whole grain food development

Owing to the health benefits associated with whole grains, there has been a sustained global effort to increase their consumption, with many countries developing guidelines for recommended amounts of whole grain intake. In China, the consumption of whole grains is low. This is due, in part, to technical obstacles in the development of whole grain foods. This review focuses on possible solutions in the whole value chain and the application of new food technologies to develop whole grain foods that taste better, have more appealing texture, are safe to consume, and better retain bioactive compounds.

Factors affecting intake, metabolism and health benefits of phenolic acids: do we understand individual variability?

INTRODUCTION

Phenolic acids are important phenolic compounds widespread in foods, contributing to nutritional and organoleptic properties.

FACTORS AFFCETING INDIVIDUAL VARIABILITY

The bioavailability of these compounds depends on their free or conjugated presence in food matrices, which is also affected by food processing. Phenolic acids undergo metabolism by the host and residing intestinal microbiota, which causes conjugations and structural modifications of the compounds. Human responses, metabolite profiles and health responses of phenolics, show considerable individual variation, which is affected by absorption, metabolism and genetic variations of subjects.

OPINION

A better understanding of the gut-host interplay and microbiome biochemistry is becoming highly relevant in understanding the impact of diet and its constituents. It is common to study metabolism and health benefits separately, with some exceptions; however, it should be preferred that health responders and non-responders are studied in combination with explanatory metabolite profiles and gene variants. This approach could turn interindividual variation from a problem in human research to an asset for research on personalized nutrition.

Food processing strategies to enhance phenolic compounds bioaccessibility and bioavailability in plant-based foods

Phenolic compounds are important constituents of plant-based foods, as their presence is related to protective effects on health. To exert their biological activity, phenolic compounds must be released from the matrix during digestion in an absorbable form (bioaccessible) and finally absorbed and transferred to the bloodstream (bioavailable). Chemical structure and matrix interactions are some food-related factors that hamper phenolic compounds bioaccessibility and bioavailability, and that can be counteracted by food processing. It has been shown that food processing can induce chemical or physical modifications in food that enhance phenolic compounds bioaccessibility and bioavailability. These changes include: (i) chemical modifications into more bioaccessible and bioavailable forms; (ii) cleavage of covalent or hydrogen bonds or hydrophobic forces that attach phenolic compounds to matrix macromolecules; (iii) damaging microstructural barriers such as cell walls that impede the release from the matrix; and (iv) create microstructures that protect phenolic compounds until they are absorbed. Indeed, food processing can produce degradation of phenolic compounds, however, it is possible to counteract it by modulating the operating conditions in favor of increased bioaccessibility and bioavailability. This review compiles the current knowledge on the effects of processing on phenolic compounds bioaccessibility or bioavailability, while suggesting new guidelines in the search of optimal processing conditions as a step forward towards the design of healthier foods.

The Profile and Bioaccessibility of Phenolic Compounds in Cereals Influenced by Improved Extrusion Cooking Treatment

The aim of this study was to investigate the effect of Improved Extrusion Cooking Treatment (IECT) on the phenolics and its bioaccessibility in cereals, represented by brown rice, wheat, and oat. Data showed that total phenolic content and total antioxidant activity in free form were significantly decreased, while the bound form was increased after IECT. After IECT, the total free phenolic acids of brown rice and wheat were significantly decreased by 5.88% and 45.66%, respectively, while the total bound phenolic acids of brown rice, wheat, and oat were significantly increased by 6.45%, 8.78%, and 9.10%, respectively. Brown rice provided the most bioaccessible phenolics and antioxidant compounds, followed by oat and wheat. IECT significantly decreased the bioaccessible phenolics of brown rice and oat by 31.09% and 30.95%, while it had minimal effect on the bioaccessible phenolics of wheat. These results showed that IECT greatly affected the phenolics and its bioaccessibiltiy of cereals, with the effect depending on cereal matrix and the sensitivity of free and bound phenolics. Furthermore, bioaccessible phenolic acids of raw and processed cereals were considerably low, and it slightly contributed to the bioaccessible phenolics.

Phenolic recovery and bioaccessibility from milled and finished whole grain oat products

Phenolics naturally present in whole grain oats are recovered well through traditional grain processing, milling and food processing.

Extrusion of barley and oat influence the fecal microbiota and SCFA profile of growing pigs

The effect of extrusion of barley and oat on the fecal microbiota and the formation of SCFA was evaluated using growing pigs as model system. The pigs were fed a diet containing either whole grain barley (BU), oat groat (OU), or their respective extruded samples (BE and OE).