Maize bran/oat flour extruded breakfast cereal: A novel source of complex polysaccharides and an antioxidant

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.

Characterization of a Mixture of Oca (Oxalis tuberosa) and Oat Extrudate Flours: Antioxidant and Physicochemical Attributes

The oca (Oxalis tuberosa) is a tuber with high starch content and excellent antioxidant properties, which can be used in the production of extruded products; however, starch-rich products can be improved nutritionally through the incorporation of fibers that can result in extrudates with beneficial health properties. The aim of this work was to develop a mixture of oca (Oxalis tuberosa) and oat extrudate flours and evaluate the antioxidant and physicochemical attributes. The results showed that a higher moisture content increased the hardness, water absorption index, and density of the extrudates; however, the solubility and expansion indexes showed an inverse pattern. The addition of oat fiber had the opposite effect from moisture content on the physicochemical properties mentioned above. The cellular antioxidant activity (CAA) of the extrudates decreased when the oat fiber increased. An inverse pattern was observed when the moisture concentration was increased. The starch hydrolysis percentage and glycemic index decreased significantly when the fiber content increased. Oat fiber contributed 67.29% and 65.04% to these parameters, respectively. Oat fiber exerted a greater effect than moisture on the collets extruded in this study according to factor contributions.

Water extractable pentosans - Quantification of ferulic acid using RP-HPLC, techno-rheological and antioxidant properties

Water extractable pentosans extracted from three varieties of oats were studied for structural analysis using ATR- FTIR, ferulic acid content using RP-HPLC, antioxidant activity by DPPH, reducing power, and metal chelating assays, and functional properties. The appearance of absorption band at 1720 cm^-1 in water extractable pentosans is assigned to the presence of aromatic esters as displayed from ATR-FTIR spectrum. All the samples exhibited non-newtonian behavior with viscosities following the order; SWEP > 20WEP > 90WEP. Bile acid binding capacity of water soluble pentosans varied significantly from 46.69 to 49.40%. RP-HPLC displayed that water extractable pentosans from SKO20 contained about 2 times higher FA (423.00 μg/100 g) compared to SWEP (250.00 μg/100 g) and 90 WEP (253.00 μg/100 g). Water soluble pentosans had DPPH scavenging activity, reducing power, and metal chelation activity in the range of 13.57-17.45 (μg α-tocopherol/g), 8.91-10.24 (μg BHT/g), and 0.55-0.76 (μg citric acid/g), respectively.

Effect of extrusion temperature and screw speed on properties of oat and rice flour extrudates

BACKGROUND

Whole oat and rice flours were mixed to develop instant flours by a high pressure and low mechanical shear extrusion process. The screw profile was designed aiming to obtain an infant food with gelatinized starch and high hydration ability. Response surface methodology was selected to study the impact of operating parameters such as temperature and screw speed (73-186 °C; 109-391 rpm) on physicochemical and pasting properties of the final extruded product. The main challenge of this study was to process high oats content, since they are characterized by high lipid and fiber content, which impact on material processing.

RESULTS

The optimal response was achieved at 170 °C and 350 rpm. The optimal expansion ratio, bulk density, water absorption index, and water solubility index were 2.24, 289.65 kg m^-3 , 6.42 g g^-1 , and 4.75 g g^-1 respectively. Overall, both temperature and screw speed affected the responses studied, except for water absorption index (only screw speed affected this response). Although lipids from oats reduce the expansion ratio of extrudates compared with samples containing higher starch proportions, their lipids protect the starch granules from mechanical degradation when higher screw speed values are used. As a result, both ungelatinized and gelatinized starches may be found in extrudates, which was confirmed by pasting property analyses.

CONCLUSION

High oat content may be efficiently processed by optimizing the extruder conditions (temperature, screw speed, and profile), improving the nutritional properties of the final product. © 2017 Society of Chemical Industry.

The effect of extrusion screw-speed on the water extractability and molecular weight distribution of arabinoxylans from defatted rice bran

Arabinoxylans (AXs) are major dietary fibre in cereals. Recently, AXs have attracted a great deal of attention because of their biological activities. These activities have been suggested to be related to the content of low molecular weight (Mw) AXs, in particular those with Mw below 32 kDa. Rice bran is a rich source of AXs. However, water extraction of AXs is difficult and often gives low yield. Extrusion processing has been used to increase the solubility of cereal dietary fibre. The aim of this research was to study the effect of extrusion screw-speeds (80 and 160) rpm on the extraction yield and Mw of water extractable AXs from rice bran. It was found that the extraction of AXs increased significantly with an increase in screw speed and was accompanied by a significant decrease in the Mw of AXs from extruded rice bran. The percentage of very low molecular weight AXs (0.79-1.58 kDa) significantly increased with increasing screw speed.

Enrichment of rice-based extrudates with Cactus Opuntia dillenii seed powder: a novel source of fiber and antioxidants

The present study investigated the effects of adding the powder of cactus Opuntia dillenii (O. dillenii) seeds on the functional properties, fiber, antioxidants and acceptability of rice-based extrudates. The control blend consisting basically of rice flour was replaced with O. dillenii seed powder at 2, 4, 6, 8, 10, 15 and 20% then extruded at the optimum processing conditions. The extruded products were evaluated for their chemical composition, functional properties, color attributes, antioxidant activity and sensory characteristics. The results revealed that adding O. dillenii seeds powder enhanced the fiber, phenolics, flavonoid contents and antioxidant activity of extrudates. Expansion, bulk density and breaking strength were significantly decreased, while water absorption index, water solubility index and oil absorption index were significantly increased compared to the control. Furthermore, the mean scores of sensory evaluation indicated clear improvements in all tested sensory attributes, which significantly increased by increasing the level of O. dillenii seed powder up to 15%. The results confirmed that O. dillenii seed powder could be incorporated in rice to develop snack products of acceptable functional, nutritional and sensory properties.

Effects of Blends of Low-Protein Winter Wheat Flour and Barley Byproducts on Quality Changes in Noodles

The physicochemical characteristics of fresh noodles made with blends of low-protein wheat flour and barley byproduct (BBP, 250 μm) were investigated. The crude protein contents (PC) of flour from Goso and Backjoong cultivars were 7.91% and 7.67%, respectively. PC and β-glucan contents from the BBP were 14.10% and 3.11%, respectively, which were higher than those in wheat flour. The water-holding capacity (WHC) of various blends was increased as a function of BBP but not gluten contents. Goso flour had the highest starch content (78.68%), with peak and final viscosities of 3,099 and 3,563 cp, respectively. Peak and final viscosities, trough, breakdown, and setback of the blends were decreased with the addition of BBP. Noodles made with Backjoong had the highest thickness score, while the hardness of noodles made with blends of Goso or Backjoong and 20% BBP were similar to those made from wheat flour only. The WHC of the samples was strongly correlated with PC, crude fiber, and β-glucan. The PC was not correlated with final viscosity, setback, thickness, hardness, gumminess, or chewiness.

Extrusion and Extruded Products: Changes in Quality Attributes as Affected by Extrusion Process Parameters: A Review

Extrusion of foods is an emerging technology for the food industries to process and market a large number of products of varying size, shape, texture, and taste. Extrusion cooking technology has led to production of wide variety of products like pasta, breakfast cereals, bread crumbs, biscuits, crackers, croutons, baby foods, snack foods, confectionery items, chewing gum, texturized vegetable protein (TVP), modified starch, pet foods, dried soups, dry beverage mixes etc. The functional properties of extruded foods plays an important role for their acceptability which include water absorption, water solubility, oil absorption indexes, expansion index, bulk density and viscosity of the dough. The aim of this review is to give the detailed outlines about the potential of extrusion technology in development of different types of products and the role of extrusion-operating conditions and their effect on product development resulting in quality changes i.e physical, chemical, and nutritional, experienced during the extrusion process.

Significance of coarse cereals in health and nutrition: a review

This review assesses the nutritional attributes of coarse cereals and also their utilization as food and as formulated foods. These cereals are laden with phytochemicals including phenolic acids, tannins, anthocyanins, phytosterols, avenenathramides and policosanols. They possess high antioxidant properties in vitro than staple cereals and fruits by different purported pathways. There are also some anti-nutritional factors that may be reduced by certain processing treatments. Several epidemiological studies show that these cereals are helpful in reducing several kinds of chronic diseases like cancers, cardiovascular diseases, type II diabetes and various gastrointestinal disorders. Being coarse in nature, they cannot replace our staple cereals, but can be used in different proportions with rice and wheat to formulate various nutritional products. They can be used to make porridges, biscuits, cakes, cookies, tortillas, bread, probiotic drinks, ladoo, ghatta, flakes and several fermented foods. The coarse cereals also have good potential in manufacturing bioethanol, paper, oil and biofilms.

Germinated grains--sources of bioactive compounds

Germination of seven selected commercially important grains was studied to establish its effects on the nutritional and chemical composition. The changes in the concentration of the nutrients, bioactive compounds and the inhibitory effect of extracts on α-glucosidase and α-amylase activities were investigated. These were measured through proximate analysis, inhibition assays and HPLC. Germinated sorghum and rye extracts inhibited (p<0.05) α-glucosidase activity, whereas barley and sorghum extracts exhibited higher inhibitory activities against α-amylase. Germinated grains contained substantial amounts of total phenolics with rye having significantly higher content compared with the non-germinated grains. Radical scavenging activities of the phenolic extracts were between 13% and 73% for non-germinated and 14% and 53% for germinated. Inositol phosphate (InsP) 4, 5 and 6 were noted in all the grains, but InsP 6 was significantly lower in concentration. This study indicates the potential of germinated barley, sorghum and rye for the development of effective physiologically bioactive compounds for the reduction of the risk of diabetic agents and colon cancer.

Utilisation of corn (Zea mays) bran and corn fiber in the production of food components

The milling of corn for the production of food constituents results in a number of low-value co-products. Two of the major co-products produced by this operation are corn bran and corn fiber, which currently have low commercial value. This review focuses on current and prospective research surrounding the utilization of corn fiber and corn bran in the production of potentially higher-value food components. Corn bran and corn fiber contain potentially useful components that may be harvested through physical, chemical or enzymatic means for the production of food ingredients or additives, including corn fiber oil, corn fiber gum, cellulosic fiber gels, xylo-oligosaccharides and ferulic acid. Components of corn bran and corn fiber may also be converted to food chemicals such as vanillin and xylitol. Commercialization of processes for the isolation or production of food products from corn bran or corn fiber has been met with numerous technical challenges, therefore further research that improves the production of these components from corn bran or corn fiber is needed.

Effect of Incorporation of Various Food By-products on Some Nutritional Properties of Rice-based Extruded Foods

Various food by-products were incorporated into rice grits and submitted to extrusion cooking to produce fortified extruded food products. The blends of various formulations of durum clear flour (8—20%), partially defatted hazelnut flour (PDHF) (5—15%), fruit waste blend (3—7%) and rice grits were extruded using single screw extruder. Response surface methodology was used to evaluate the effects of process variables, namely the feed moisture content (12—18%), barrel temperature (150—175 °C) and screw speed (200—280 rpm), and change in feed composition on total phenolic content, antioxidant activity, percent starch gelatinization and starch digestibility of the extrudates. Extrusion cooking process significantly increased the level of phenolic compounds and starch digestibility of extruded products. Increasing PDHF and fruit waste content caused increase in total phenolic content and antioxidant activity of the extruded samples, whereas percent starch gelatinization and digestibility values decreased. Moisture content and temperature significantly influenced the total phenolic content, antioxidant activity, percent starch gelatinization and starch digestibility values. In extruded samples, positive correlations were determined between antioxidant activity and total phenolic matter and percent starch gelatinization and the starch digestibility values, respectively.