Effect of sand roasting on beta glucan extractability, physicochemical and antioxidant properties of oats

Extraction, purification, structural characteristics, bioactivity and potential applications of polysaccharides from Avena sativa L.: A review

Avena sativa L. (A. sativa L.), commonly known as oat, is a significant cereal grain crop with excellent edible and medicinal value. Oat polysaccharides (OPs), the major bioactive components of A. sativa L., have received considerable attention due to their beneficial bioactivities. However, the isolation and purification methods of OPs lack innovation, and the structure-activity relationship remains unexplored. This review emphatically summarized recent progress in the extraction and purification methods, structural characteristics, biological activities, structure-to-function associations and the potential application status of OPs. Different materials and isolation methods can result in the differences in the structure and bioactivity of OPs. OPs are mainly composed of various monosaccharide constituents, including glucose, arabinose and mannose, along with galactose, xylose and rhamnose in different molar ratios and types of glycosidic bonds. OPs exhibited a broad molecular weight distribution, ranging from 1.34 × 105 Da to 4.1 × 106 Da. Moreover, structure-activity relationships demonstrated that the monosaccharide composition, molecular weight, linkage types, and chemical modifications are closely related to their multiple bioactivities, including immunomodulatory activity, antioxidant effect, anti-inflammatory activity, antitumor effects etc. This work can provide comprehensive knowledge, update information and promising directions for future exploitation and application of OPs as therapeutic agents and multifunctional food additives.

Cereal β-d-Glucans in Food Processing Applications and Nanotechnology Research

Cereal (1,3)(1,4)-β-d-glucans, known as β-d-glucans, are cell wall polysaccharides observed in selected plants of grasses, and oats and barley are their good natural sources. Thanks to their physicochemical properties β-d-glucans have therapeutic and nutritional potential and a specific place for their functional characteristics in diverse food formulations. They can function as thickeners, stabilizers, emulsifiers, and textural and gelation agents in beverages, bakery, meat, and extruded products. The objective of this review is to describe the primary procedures for the production of β-d-glucans from cereal grains, to define the processing factors influencing their properties, and to summarize their current use in the production of novel cereal-based foods. Additionally, the study delves into the utilization of β-d-glucans in the rapidly evolving field of nanotechnology, exploring potential applications within this technological realm.

Comparison of Nutritional Composition and Antioxidant Properties of Pulverized and Unutilized Portions of Waxy Barley

To promote the use of waxy barley bran, an underutilized resource, samples of waxy barley were divided into three parts: polished waxy barley powder (PWBP), inner bran layer powder (IBLP), and outer bran layer powder (OBLP). The color and appearance, general properties, minerals, vitamins, β-glucan, antioxidant properties, and aroma of each part were compared. In terms of appearance and color, IBLP and OBLP appeared more yellow than PWBP; general components that were more abundant in IBLP and OBLP compared with PWBP were protein, fat, and ash. IBLP and OBLP had characteristically high values of Mg and Zn, monounsaturated and polyunsaturated fatty acids, vitamin B₁, total polyphenol content, H-ORAC, and DPPH. In particular, the vitamin B₁ content of OBLP was approximately 10 times higher than that of PWBP, and Mg and Zn content was more than five times higher than in PWBP. The β-glucan content of IBLP and OBLP was lower than that of PWBP, but relatively high. GC-MS analysis revealed that hexanal was the aroma component common to all three samples, and the peak areas were in the order of PWBP > OBLP > IBLP.

Effect of different pretreatments on antioxidant activity of oats grown in the Himalayan region

In this work the different varieties of oats were subjected to three pre-treatments such as germination, sand roasting and γ-irradiation. The pretreated oat grains were evaluated for phenolic content, flavonoid content and antioxidant activity. RP-HPLC displayed that the amount of ferulic acid, chlorogenic acid, kaempferol, ellagic acid and epicatechin in native, roasted and γ-irradiated oats varied in the range of 2.51-3.23, 0.97-1.89, 4.35-5.33, 1.56-2.197 and 3.387-10.8 µg/100 g, respectively. Total phenolic content (TPC) expressed as µg GAE/g and µg FAE/g and total flavonoid content (TFC) expressed as µg rutin equivalent/g was found highest in germinated samples. Study reported increase in antioxidant activity in the following order; γ-irradiation > germination > roasting > native. It was concluded that the different pretreatments enhanced antioxidant properties of the oat grains therefore can be efficiently utilized as food or functional ingredient in various food systems.

Novel infrared puffing: Effect on physicochemical attributes of puffed rice ( Oryza sativa L.)

The effect of novel infrared (IR) puffing and various IR powers (350, 450, and 550 Watts [W]) at various distances (10, 20, and 30 cm) on physicochemical characteristics of puffed rice (puffing properties, color, total phenolic content [TPC], antioxidant activity, peroxide value, and morphology) was investigated. By reducing the distance and increasing the IR power, the volume puffing was significantly increased (p < .05), and bulk density was significantly decreased (p < .05) but there was no significant difference in the length/breadth ratio. The IR puffing effect on color, the TPC, antioxidant activity, and food compounds' analysis through Fourier transform infrared (FTIR) spectra were significant (p < .05) during IR puffing. The scanning electron microscopy (SEM) images showed that by increasing the IR power and decreasing the sample distance from the IR source, the size of protrusions was increased (the volume of the protrusions). The maximum increase in the protrusions size was observed in 10 cm distance and 550 W power of IR. This is the first report on the IR puffing of rice and according to the results, the IR puffing technology has a high efficiency at the rice puffing.

Impact of thermally induced wall breakage on the structural properties of water-soluble polysaccharides in chickpeas

The present work aimed to elucidate the influence of wall breakage induced by thermal processing on the molecular, structural, and antioxidant activities of water-soluble polysaccharides in chickpeas. Different extents of cell wall disruption were observed by fluorescence microscopy in chickpea cotyledons. Moreover, a decreasing fluorescence intensity of cell wall fragments was observed in the flour residues upon heat fluidization, autoclaving, and microwave heating, and the polysaccharide extraction rates were increased by 31.47%, 25.52%, and 9.79%, respectively. Furthermore, WPUCP, WPHCP, WPMCP, and WPACP (water-soluble polysaccharides from unprocessed, heat fluidized, microwaved, and autoclaved chickpeas, respectively) were RG-I (rhamnogalacturonan-I)-enriched pectic polysaccharides composed of galactose, arabinose, galacturonic acid, and rhamnose. After chickpea thermal processing, the degrees of branching decreased to 2.87, 3.79, and 2.53 in WPHCP, WPMCP, and WPACP, respectively, and the molecular weights were reduced by 46.46%, 24.83%, and 59.91%, respectively. Structural analysis showed that the semicrystalline regions of WPHCP, WPMCP, and WPACP were slightly damaged without changing the functional groups, but their thermal stability decreased. Interestingly, WPACP formed an ordered conformation (microporous network structure) through the formation of hydrogen bonds. Moreover, the antioxidant activities of WPHCP, WPMCP, and WPACP were enhanced, and the strongest radical scavenging activity was observed for WPHCP.

Biochemical assessment of oat genotypes revealed variability in grain quality with nutrition and crop improvement implications

Oat is a potent source of nutrients and bioactive compounds offering potential health benefits and role in combating micronutrient malnutrition problems. To exploit nutritional and quality traits of oats, a biochemical assessment of 112 oat genotypes was conducted. The high range of variability for total phenol (1.7-31.3 mg/g), β-glucan (1.0-8.0 mg/g), calcium (1.91-4.34 mg/g), zinc (3.80-6.50 mg/100 g), iron (0.66-4.89 mg/100 g) and manganese (2.88-8.0 mg/100 g) was revealed among genotypes. A higher amount of iron and zinc was found in genotypes OS-6, HFO-638, HFO-915 & HFO-918, whereas, elevated levels of manganese and zinc were recorded in genotypes OS-403 & OL-1804. The results revealed groups of low phytic acid oat genotypes containing high crude protein (HFO-52, HFO-270, HFO-330), β-glucan (HFO-62, HFO-588, HFO-926). A significant positive correlation was obtained between copper with iron, manganese, and calcium content. These findings could be useful for developing value-added oat food products and novel oat varieties.

Development of grain-based carbonated beverage premix using maize (Zea Mays), Bengal gram (Cicer Arietinum), and finger millet (Eleusine Coracana)

A grain based carbonated beverage premix with adequate nutritional composition and fizzing effect in the form of dry powder has been developed in the current study. Maize and Bengal gram were roasted at temperature 160-180 °C while finger millet at 80-120 °C for 10-30 min. The optimized conditions for the roasting of maize, Bengal gram and finger millet were 180 °C for 10 min, 180 °C for 27 min and 110 °C for 30 min, respectively using face centred composite design and response surface methodology (RSM). The formulation of the beverage premix obtained using linear programming was in the proportion of 30 g, 30 g, 10 g, 20 g and 10 g of roasted maize, Bengal gram, finger millet flours, sugar (powdered) and pea protein isolate, respectively. The effect of carbonation was found to be best with 8% carbonation powder concentration and 1:4 beverage premix to water ratio which showed an overall acceptability of 7.7. The developed carbonated beverage premix was light in color with a positive L* value of 79.01 ± 0.12 and slightly acidic with a pH of 5.56 ± 0.10. The nutritional composition of the final product comprised of 16% protein and several minerals viz. Fe (11.67 mg/100 g), Ca (36.67 mg/100 g) and Mg (86.26 mg/100 g).

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13197-021-05175-5.

Holistic View of Starch Chemistry, Structure and Functionality in Dry Heat-Treated Whole Wheat Kernels and Flour

Heat treatment is used as a pre-processing step to beneficially change the starch properties of wheat flour to enhance its utilisation in the food industry. Heat-treated wheat flour may provide improved eating qualities in final wheat-based products since flour properties predominantly determine the texture and mouthfeel. Dry heat treatment of wheat kernels or milled wheat products involves heat transfer through means of air, a fluidising medium, or radiation—often resulting in moisture loss. Heat treatment leads to changes in the chemical, structural and functional properties of starch in wheat flour by inducing starch damage, altering its molecular order (which influences its crystallinity), pasting properties as well as its retrogradation and staling behaviour. Heat treatment also induces changes in gluten proteins, which may alter the rheological properties of wheat flour. Understanding the relationship between heat transfer, the thermal properties of wheat and the functionality of the resultant flour is of critical importance to obtain the desired extent of alteration of wheat starch properties and enhanced utilisation of the flour. This review paper introduces dry heat treatment methods followed by a critical review of the latest published research on heat-induced changes observed in wheat flour starch chemistry, structure and functionality.

Effect of heat-moisture treatment of germinated black rice on the physicochemical properties and its utilization by lactic acid bacteria

The heat susceptibility of starch granule structure has been considering as significant limitation of germinated black rice (GBR) using in food processing industry. Therefore, this study aimed to improve the physicochemical and antioxidation property as well as its effect on the probiotics of GBR by heat moisture treatment (HMT). Black rice germinated at 37.5 °C for 12, 24, and 36 h were studied. Ultrastructural image of each sample was visualized through scanning electron microscope. The results illustrated 24 h-GBR retain its former shape with rough surface. Subsequently, 24 h-GBR was structurally modified by HMT with moisture levels of 20% and 25% for 1 and 2 h. The results showed that pasting properties of HMT-treated GBR were improved. This was particularly on, GBR using HMT condition of 25% moisture for 2 h decrease in breakdown viscosity was shown. Moreover, phenolic content of HMT-treated GBR was higher than those of GBR. Besides, the number of the Lactobacillus paracasei TOKAI 13 was increased in GBR and HMT-treated GBR with counts of 10.08 ± 0.83 Log CFU/ml and 9.31 ± 0.33 Log CFU/ml, respectively, with significant increases in antioxidant property. Therefore, the HMT-GBR could be utilized as an alternative functional ingredient in food processing products.

Heat Treatment of Reishi Medicinal Mushroom (Ganoderma lingzhi) Basidiocarp Enhanced Its β-glucan Solubility, Antioxidant Capacity and Lactogenic Properties

The effect of heat treatment on dried fruiting bodies of Reishi medicinal mushroom (Ganoderma lingzhi) is investigated. Control and samples treated for 20 min at temperatures of 70, 120, 150 and 180 °C were subjected for their free radical scavenging capacity, different glucans and total phenolic content determination. The growth rate of Escherichia coli and Lactobacillus casei supplemented with control and heat-treated samples is also investigated. The roasted mushroom samples at 150 °C and 180 °C showed the highest level of β-glucan (37.82%) and free radical scavenging capacity on 2,2-diphenyl-1-picrylhidrazyl (DPPH•) and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS•+). The content of total phenolics (TPC) was also influenced by heat treatment and significantly higher TPC values were recorded in samples treated at 120 °C and 150 °C. The presence of reducing sugars was only detected after heat treatment at 150 °C (0.23%) and at 180 °C (0.57%). The heat treatments at 120, 150 and 180 °C, significantly attenuated the number of colony-forming units (CFU) of pathogenic E. coli, in a linear relationship with an elevated temperature. The supplementation of heat-treated Reishi mushroom at 120 °C resulted in the highest growth rate of probiotic L. casei. The obtained results in this study revealed the significant effect of short-term heat treatment by enhancing the antioxidant capacity, β-glucan solubility and prebiotic property of the dried basidiocarp of Reishi mushroom.

Quality characteristics of sand, pan and microwave roasted pigmented wheat (Triticum aestivum)

Present study investigated the effect of sand, pan and microwave roasting on physico-chemical, functional and rheological properties of yellow (YW), purple (PW), and black wheat (BW). All roasting methods enhanced the browning index (BI), water absorption capacity (WAC) and oil absorption capacity (OAC) roasted wheat flour. Microwave roasting showed significantly higher impact on BI (58.61% for YW, 131% for BW and 83.85% for PW) and WAC (47.93% for YW, 44.63% for BW and 32.09% for PW). However, the decrease in density, emulsifying capacity (EC), foaming capacity (FC), total phenolic content (TPC), total flavonoid content (TFC), and total anthocyanin content (TAC), and antioxidant activity was observed on roasted wheat flour. Roasting also affected the pasting properties of wheat flours and peak, trough, breakdown and final viscosity decreased.

Effect of thermal treatment on the physicochemical, ultrastructural and nutritional characteristics of whole grain highland barley

Highland barley (HB) was subjected to three thermal treatments (heat fluidization, microwave, and baking) and assessed for physicochemical, ultrastructural and nutritional properties. After thermal treatments, the hardness, bulk density, thousand kernel weight, length/breadth ratio, and color difference decreased significantly, while puffing index increased. Meanwhile, the formation of fissure was observed in the appearance. Microstructure images illustrated that numerous micropores were evenly distributed in the endosperm structure, and aleurone layer cells were deformed by compression. Furthermore, a dramatically disruption of endosperm cell walls and slightly deformation of outer layers were observed by confocal laser scanning microscopy. Moreover, a notably decrease in total phenolics (14.02%-36.91%), total flavonoids (25.28%-44.94%), and bound phenolics (8.99%-27.53%) was detected, while free phenolics (8.81%-43.40%), β-glucan extractability (4.71%-43.66%), antioxidant activity (71.87%-349.77%), and reducing power (3.05%-56.13%) increased significantly. Greatest increase in nutritional values was caused by heat fluidization, which possessed the potential for development of ready-to-eat functional foods.

Viscoelastic and Textural Characteristics of Gels Obtained from Potato Starch Roasted under Several Temperature-Time Conditions

The influence of roasting conditions on the potato starch (PS) composition, solubility, crystallinity, gel-forming thermal profiles, and texture of the corresponding gels was studied. Thermorheological testing of roasted starches with (RPS) and without (RPSI) the soluble fraction was conducted on a stress-controlled rheometer. Texture profile analysis (TPA) was used to determine the RPS final gel texture. Solubility tests showed equivalent effects of starch roasting for samples treated at 190°C for 8 h (RPS190-8), 210°C for 6 h (RPS210-6), and 230°C for 4 h (RPS230-4). The apparent amylose content of RPS linearly increased with the decreasing degree of crystallinity. Elastic (G′) and viscous (G″) properties of RPS depended markedly on apparent amylose content and crystallinity. G′gel values of roasted starches linearly increased with the amylose content suggesting a promotion of the amylose breakdown with roasting temperature. Gels prepared with RPS roasted between 120 and 170°C exhibited intermediate strength and fully thermal reversible features. Roasting between 190 and 210°C favoured strong and fully thermal reversible gels. Although RPS230-4 gels exhibited similar strength to RPS190-8 and RPS210-4, no fully thermal reversible gels were obtained. The soluble fraction removal led to a drop the RPSI gels strength with increasing roasting temperature. No water syneresis was identified for RPS gels during one-week ageing, except for RPS230 gels. Relationships between textural parameters from TPA and viscoelastic gel properties determined by rheology were established.

Optimizing Physiochemical and Sensory Properties of Infrared-Hot Air Roasted Sunflower Kernels Using Response Surface Methodology

Roasting sunflower kernels is a key process in production of nuts. In this study, the effect of roasting conditions, including hot air temperature (120–160°C), infrared (IR) power (400–600 W) and roasting time (3–10 min) on energy and specific energy consumption, color parameters (L∗, a∗, b∗, ΔE, BI, SI, WI, and h°), texture, moisture content, chemical properties (pH and total phenolic contents, peroxide value (PV), and sensory properties of sunflower kernel were investigated. In addition, the best models for the responses were obtained, and the proper roasting conditions were determined using response surface methodology (RSM). A quadratic model was proposed for color change (L∗, ΔE, SI, and WI), moisture and total phenol contents, linear relation for a∗, b∗, h°, and 2FI for BI, texture, PV, and pH. Roasting at 425.7 W IR power and 124.3°C for 3.7 min was found to be convenient or proper roasting conditions.

Effect of Soaking and Roasting on the Physicochemical and Pasting Properties of Soybean Flour

The effects of soaking and roasting on the physicochemical and pasting properties of soybean flour were evaluated. Soybean seeds were soaked overnight in tap water for 0–72 h, hand dehulled, dried, and part of the sample was roasted. Roasted and unroasted soy beans were milled into flour and analyzed. The results showed that the total carbohydrates (22.8–27.9 g/100 g), the ash content (3.5–3.6 g/100 g), and the total polyphenols (0.29–0.51 g/100 g) did not significantly change during both the soaking and roasting processes. However, the total proteins (35.8–46.0 g/100 g) and lipid contents (21.4–29.5 g/100 g) were significantly (p < 0.05) affected only by soaking, with a decrease in total protein and an increase in lipid contents. Phytate content (0.22–0.26 g/100 g) decreased significantly (p < 0.05) only with roasting. The tannins (0.01–0.30 g/100 g) and soluble proteins (4.0–29.0 g/100 g) significantly (p < 0.05) diminished with both treatments. There was a significant increase in the least gelation concentration (20–30 g/100 mL), a decrease in the swelling power (1.3–2.0 mL/mL), and consequently, reduction in the viscosity (range peak viscosity 18–210 cP) of the flour slurry after soaking and roasting. All these qualities—needed for producing nutritious flour for infants—highlighted the efficiency of these endogenous technologies.