Antioxidant properties of tartary buckwheat extracts as affected by different thermal processing methods

Flaking of millets and its impact on bioactivity, pasting, digestibility, structural and thermal properties

Five different millets (foxtail, little, barnyard, kodo and browntop) with and without sprouting were subjected to flaking. Phytic acid and phenolic content tends to decrease significantly, whereas antioxidant activity increased up to 77.32% on flaking of millets. A significant decrease in peak and final viscosity was observed in millet flakes. A-type diffraction pattern was predominant for unsprouted millets whereas the flaked millets showed V-type crystallinity. The protein digestibility significantly increased up to 37.77% in flakes made from sprouted millets. The mineral bioavailability upon flaking of millets increased, especially Ca (88.22% for little), Fe (43.04% for barnyard) and Zn (61.77% for kodo), which is attributed to the reduction in phytic acid. Flaking, however, led to an increase in rapidly and slowly digestible starch with a corresponding decrease in resistant starch. Among the unsprouted and sprouted millet flakes, foxtail received the highest sensory scores for overall acceptability.

Fermentation of millet bran with Bacillus natto: enhancement of bioactivity levels and the bioactivity of bran extract

BACKGROUND

Millet bran (MB), a byproduct of millet production, is rich in functional components but it is underutilized. In recent years, researchers have shown that fermentation can improve the biological activity of cereals and their byproducts. This study used Bacillus natto to ferment millet bran to improve its added value and broaden the application of MB. The bioactive component content, physicochemical properties, and functional activity of millet bran extract (MBE) from fermented millet bran were determined.

RESULTS

After fermentation, the soluble dietary fiber (SDF) content increased by 92.0%, the β-glucan content by 164.4%, the polypeptide content by 111.4%, the polyphenol content by 32.5%, the flavone content by 16.4%, and the total amino acid content by 95.4%. Scanning electron microscopy revealed that the microscopic morphology of MBE changed from complete and dense blocks to loosely porous shapes after fermentation. After fermentation, the solubility, water-holding capacity, and viscosity significantly increased and the particle size decreased. Moreover, the glucose adsorption capacity (2.1 mmol g-1), glucose dialysis retardation index (75.3%), and α-glucosidase inhibitory (71.4%, mixed reversible inhibition) activity of the fermented MBE (FMBE) were greater than those of the unfermented MBE (0.99 mmol g-1, 32.1%, and 35.1%, respectively). The FMBE presented better cholesterol and sodium cholate (SC) adsorption properties and the adsorption was considered inhomogeneous surface adsorption.

CONCLUSION

Fermentation increased the bioactive component content and improved the physicochemical properties of MBE, thereby improving its hypoglycemic and hypolipidemic properties. This study not only resolves the problem of millet bran waste but also encourages the development of higher value-added application methods for millet bran. © 2024 Society of Chemical Industry.

Dry-air roasting impact on physicochemical, functional, antioxidant properties, phenolic profile and Maillard reaction products of flaxseed flour and cake flour

The study investigated and compared physicochemical, functional, antioxidant properties, phenolic profile and Maillard reaction products (MRP) of flaxseed flour (FF) and flaxseed cake flour (FCF) upon dry-air roasting (DaR) of flaxseeds at 140, 160 and 180 °C for 5 and 10 min. This information on FF and FCF is limited and has considerable gaps. The raw FF exhibited higher fat, ash, antioxidant and functional properties while lower protein than the FCF. Upon increasing DaR conditions, the ash and protein increased in FCF and decreased in FF. DaR at 180 °C for 10 min augmented water solubility index, ΔE, MRP, free rutin and syringic acid, bound epicatechin, gallic acid and syringic acid while lowered moisture, L*, b*, hue, chroma, potassium, iron, selenium, emulsion indexes, caffeic acid, flavonoids and free resveratrol in FF and FCF. In conclusion, DaR improves phenolic profile, antioxidant properties, MRP, water solubility and oil absorption capacity of FF and FCF.

Impact of Cooking Methods on Phenolic Acid Composition, Antioxidant Activity, and Starch Digestibility of Chinese Triticale Porridges: A Comparative Study between Atmospheric Pressure and High Pressure Boiling

Water boiling under atmospheric pressure (CAP) and water boiling under high pressure (CHP) are two popular domestic cooking methods for Chinese porridge making. In this study, we aimed to evaluate the effects of these two methods on the phenolic acid composition, antioxidant activity, and starch digestibility of triticale porridges. The contents of total free and total bound phenolic acids in the CHP sample were 1.3 and 1.6 times higher than those in the CAP counterpart, respectively, although the DPPH and ABTS values of these two samples were comparable. CAP induced more small pieces of starch than CHP, and the gelatinization enthalpy was 19% higher in the CHP sample than that in the CAP. Both cooking methods increased the starch digestibility, while the CHP sample (58.84) showed a lower GI than the CAP (61.52). These results may promote the application of triticale in health-promoting staple foods.

Effect of subcritical water flash release processing on buckwheat flour properties

BACKGROUND

Buckwheat (Fagopyrum esculentum) is rich in bioactive components. However, many of these components are trapped within cellular structures, making them inaccessible. Buckwheat flour was hydrothermally modified using subcritical water coupled with a flash pressure release (SCWF). The effects of the SCWF parameters (120, 140, and 160 °C and hold times of 0, 15, and 30 min) on the flour's structure, physicochemical, and functional properties were studied relative to the raw flour.

RESULTS

Treatment deepened the flour color with increasing processing temperatures and hold times. Starch content remained unchanged though its granular structure was disrupted. SCWF treatments lowered total phenolic content compared with the raw flour, except for 160 °C-30 min, where total phenolic content increased by 12.7%. The corresponding antioxidant activities were found consistent with phenolic content. Soluble and insoluble dietary fiber amounts were not substantially influenced at 120 and 140 °C, whereas treatments at 160 °C (15 and 30 min hold) decreased soluble dietary fiber while increasing insoluble dietary fiber. Protein content increased 70-109% in some treatments, suggesting greater protein accessibility. Water-holding capacity significantly increased for flour treated at 120 °C, whereas only slight improvements occurred at 140 and 160 °C.

CONCLUSIONS

Subcritical water flash processing can modify the compositional and functional properties of buckwheat flour depending on the choice of reaction conditions. Observed changes were consistent with alteration of the flour's cellular structure and allow some components to become more accessible. The resulting SCWF-modified buckwheat flours provide new food ingredients for potential use in ready-to-eat foods and spreads with improved health benefits. Published 2022. This article is a U.S. Government work and is in the public domain in the USA.

Fermentation of rose residue by Lactiplantibacillus plantarum B7 and Bacillus subtilis natto promotes polyphenol content and beneficial bioactivity

The present study evaluated the effect of fermentation with Lactiplantibacillus plantarum B7 and Bacillus subtilis natto on phenolic compound levels and enzyme activity, as well as antioxidant capacity of the rose residue. Results showed that the polyphenol content of rose residue was significantly increased from 16.37 ± 1.51 mg/100 mL to 41.02 ± 1.68 mg/100 mL by fermentation at 37 °C and 2.0% (v/v) inoculum size for 40 h. The flavone, soluble dietary, and protein contents were also enhanced by almost 1-fold, 3-fold, and 1-fold, respectively. Fifteen phenolic compounds were quantified in the fermented broth, among which the concentration of gallic acid, quercetin, and p-coumaric acid increased by 5-fold, 4-fold, and almost 8-fold, respectively. Chlorogenic acid was a new phenolic compound produced during fermentation. Moreover, the fermented rose residue presented higher superoxide dismutase, α-amylase, and protease activity. ABTS^•+, hydroxylradical, and DPPH^• scavenging activity increased by 60.93%, 57.70%, and 37.00%, respectively. This provides an effective means of transforming rose residue into a highly bioactive value-added substance.

Influence of ozonation and roasting on functional, microstructural, textural characteristics, and aflatoxin content of groundnut kernels

The present study was conducted to evaluate the influence of ozonation, roasting and their combination on the moisture content, color, functional, structural, textural components, and aflatoxins in groundnut kernels. Samples were subjected to three treatments namely, dry roasting (R): 166°C for 7 min; gaseous ozone treatment (O): 6 mg/L for 30 min; combined ozonation-roasting (OR): gaseous ozonation at 6 mg/L for 30 min followed by dry roasting at 166°C for 7 min. The ozonated-roasted samples had the lowest moisture content (3.45%), the highest total phenolic content (4.18 mg gallic acid equivalents/100 g), and antioxidants capacity (69.59%). The treatments did not induce significant changes in color of kernels (p < .05). Scanning electron microscopy indicated cracking of granules in roasted and swelling in ozonated kernels whereas more uniform orientation of granules was observed in ozonated-roasted kernels. Roasted and ozonated kernels indicated a significant reduction of fracturability force to 54.60 and 14.11%, respectively, whereas ozonated-roasted samples demonstrated a nonsignificant increase (4.37%). An increase in wave number of ozonated samples to 3,289.37 cm^-1 in Fourier transform infrared (FTIR) spectrum (FTIR) indicated stretching in OH groups. FTIR spectrum of ozonated-roasted kernels suggested the formation of a new compound with CC and CC groups. The major aflatoxin B1 was reduced to maximum, that is, 100% in ozonated-roasted kernels followed by ozonated (80.95%) and roasted (57.14%) samples. The findings indicate that the ozonation-roasting treatment had a prominent role in the enhancement of functional compounds, structural and textural attributes along with the considerable reduction in aflatoxin content.

A Review of the Pharmacological Potential of Spatholobus suberectus Dunn on Cancer

Spatholobus suberectus Dunn (SSD) has been extensively employed in Traditional Chinese Medicine to treat several ailments. SSD and its active compounds are effective therapeutic agents for treating a variety of diseases with negligible side effects. Therefore, we aimed to investigate its phytochemistry, pharmacology, and potential therapeutic effects exclusively in cancer prevention and treatment. Phytochemical and pharmacological information was collected and arranged in a rational order. SSD has been frequently attributed to having antioxidant, anti-diabetic, anti-inflammatory, hematopoietic, neuroprotective, antimicrobial, and anticancer properties. Evidence has indicated that the bioactive constituents in SSD have attracted increasing scientific attention due to their preventive role in cancers. Further, the present review provides the current information on the health implications of SSD, thus allowing for future clinical trials to explore its restorative benefits. All data of in vitro and animal investigations of SSD, as well as its effect on human health, were obtained from an electronic search and library database. The diverse pharmacological potential of SSD provides an opportunity for preclinical drug discovery, and this comprehensive review strongly indicates that SSD is an excellent anti-tumorigenic agent that modulates or prevents breast cancer.

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.

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.

Antioxidative Activity Evaluation of High Purity and Micronized Tartary Buckwheat Flavonoids Prepared by Antisolvent Recrystallization

Tartary buckwheat, a healthy food, is associated with a reduced risk of certain human chronic diseases. However, the bioactive component flavonoids in Tartary buckwheat have poor solubility and low absorption in vivo. To improve these points, 60.00% Tartary buckwheat total flavonoids (TFs) were obtained by ethanol refluxing method, which were purified and micronized by antisolvent recrystallization (ASR) using methanol as a solvent and deionized water as an antisolvent. By using High Performance Liquid Chromatography (HPLC) and electrospray ionized mass spectrometry (ESI-MS), the main flavonoid in pure flavonoids (PF) were rutin (RU), kaempferol-3-O-rutinoside (KA) and quercetin (QU); the content of TF is 99.81% after purification. It is more worthy of our attention that micronized flavonoids contribute more to antioxidant activity because of good solubility. These results provide a theoretical reference for the micronization of other flavonoids.

Nutritional Quality of Four Novel Porridge Products Blended with Edible Cricket (Scapsipedus icipe) Meal for Food

Currently, no data exist on the utilization of the newly described cricket species (Scapsipedus icipe) meal as additive in food products, though they have high protein (57%) with 88% total digestibility as well as a variety of essential amino acids. This article presents the first report on the effects of processing techniques and the inclusion of cricket meal (CM) on the nutrient and antinutrient properties of four porridge products compared to a popularly consumed commercial porridge flour (CPF). Porridge enriched with CM had significantly higher protein (2-folds), crude fat (3.4-4-folds), and energy (1.1-1.2-folds) levels than the CPF. Fermented cereal porridge fortified with CM had all three types of omega-3 fatty acids compared to the others. The vitamin content across the different porridge products varied considerably. Germinated cereal porridge with CM had significantly higher iron content (19.5 mg/100 g). Zinc levels ranged from 3.1-3.7 mg/100 g across the various treatments. Total flavonoid content varied significantly in the different porridge products. The phytic acid degradation in germinated and fermented porridge products with CM was 67% and 33%, respectively. Thus, the fortification of porridge products with cricket and indigenous vegetable grain powder could be considered an appropriate preventive approach against malnutrition and to reduce incidences in many low-and middle-income countries.

Culture matters: A systematic review of antioxidant potential of tree legumes in the semiarid region of Brazil and local processing techniques as a driver of bioaccessibility

Ethnobotanical studies report that human populations from the Brazilian Caatinga biome use tree legumes (Fabaceae) with medicinal and food purposes. Our study provides a systematic review of the available published information concerning the antioxidant potential of Hymenaea courbaril L. (jatobá), Libidibia ferrea (Mart. Ex Tul.) L.P.Queiroz (jucá), and Dioclea grandiflora Mart. Ex Benth. (mucunã). Furthermore, in this paper, we infer the possible effects of local processing techniques applied to these plants on their antioxidant potential. In order to achieve these goals, we reviewed 52 articles, including studies from ethnobiology (n = 17), chemistry (n = 32), and food studies testing antioxidant activity (n = 17), excluding 14 repetitions. We found that these legume species can inhibit the formation of free radicals and this potential action varies among different parts of the plant. Probably, the presence of phenolic compounds such as phenolic acids and flavonoids, which are not uniformly distributed in the plants, explain their antioxidant activity. Local processing techniques (i.e., roasting, milling) affect the bioaccessibility of antioxidant components of tree legumes, inducing both positive and negative effects. However, studies about the antioxidant potential did not consider local processing techniques in their analyses. Our study highlights that culture is a fundamental driver of nutritional and pharmacological outcomes related to edible resources since it determines which parts of the plant people consume and how they prepare them. Hence, ignoring cultural variables in the analysis of antioxidant activity will produce inaccurate or wrong scientific conclusions.

Enrichment in Different Health Components of Barley Flour Using Twin-Screw Extrusion Technology to Support Nutritionally Balanced Diets

Due to its good dietary role, barley has attracted a growing amount of interest for the manufacture of functional foods in recent years. In barley, a number of bioactive components, including as phenolic compounds, have been discovered, and barley extrudates could be used to formulate various processed foods, including ready-to-eat cereals, baby, and pet foods and support nutritionally balanced diets. This study was conducted to investigate the effect of extrusion processing on resistant starch (RS), glycemic index (GI), and antioxidant compounds of barley flour. The L^* and ΔE values of barley flours decreased significantly (p < 0.05) after extrusion is done at 150 and 180°C. The a^* and b^* values, however, increased after extrusion. Extrusion increased antioxidant activity (AOA), metal chelating activity (MCA), and ABTS⁺ scavenging activity, whereas total phenolic content (TPC) and total flavonoids content (TFC) decreased. Barley extrudates at 150 and 180°C showed decreased TPC by 16.4–34.2% and 23.4–38.1%. Moreover, improved RS and reduced GI values were recorded for barley extrudates as compared to barley non-extrudates. Therefore, extrusion of barley could be an alternative to produce pregelatinized barley flour with improved RS low GI values and improved antioxidant potential.

Effects of Airflow Ultrafine-Grinding on the Physicochemical Characteristics of Tartary Buckwheat Powder

Five different ultrafine milled flours (UMFs) were prepared from Tartary buckwheat via airflow ultrafine-grinding at different grinding pressures. The airflow ultrafine-grinding resulted in marked differences in particle size (from 100 to 10 μm). The UMFs were all brighter in appearance (higher L*) than Tartary buckwheat common flour (TBCF). Illustrated by the example of 70 °C, the UMFs were also found to have a greater water holding capacity (from 4.42 g/g to 5.24 g/g), water solubility (from 12.57% to 14.10%), and water solubility index (from 5.11% to 6.10%). Moreover, as the particle sizes reduced, the moisture content decreased (from 10.05 g/100 g DW to 7.66 g/100 g DW), as did the total starch content (from 68.88 g/100 g DW to 58.24 g/100 g DW) and the protein content (from 13.16% to 12.04%). However, the grinding process was also found to have negative effects on the mineral content of the Tartary buckwheat. Additionally, several substantial variations were found in their hydration properties along with grinding pressure changes in the differently ground UMFs. Consequently, fine Tartary buckwheat powders of a bright yellow color, with superior food processing properties, were prepared in this study by airflow ultrafine-grinding.

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.

Quality characteristics of buckwheat (Fagopyrum esculentum) based nutritious ready-to-eat extruded baked snack

The study aimed to utilize buckwheat and bread waste to develop ready to eat snack with reduced fat, enriched protein, dietary fiber and minerals. Base flour constituting of buckwheat flour (BF) and rice flour in the ratio of 90:10 was replaced with bread powder (BP) at varying levels (0-80%). The gelatinization temperature of base flour was 67 °C and it decreased with increasing amount of BF. The breaking strength of the extruded snack with varying amount of BP, fat and chilli powder were in the range between 3.46-2.04 N, 1.56-1.26 N and 1.5-1.89 N respectively. Physical and sensory analyses indicate that 40% BP, 8% fat and 1% chilli powder were optimum to obtain extruded snack with desirable characteristics. The ready to eat snack contained 10.64%, 15.33% and 7.45% of fat, protein and total dietary fiber respectively. Minerals present were 169 mg/100 g of magnesium, 46 mg/100 g of calcium, 4.5 mg/100 g of iron and 3.46 mg/100 g of zinc. Bread waste can thus be utilized in producing a healthy ready to eat snack.

Effects of Various Preextraction Treatments of Crinum asiaticum Leaf on Its Anti-Inflammatory Activity and Chemical Properties

Crinum asiaticum Linn. has been used in Thai traditional medicine to relieve inflammatory symptoms and treat osteoarthritis. There have been reports on its potent anti-inflammatory property but nothing on the effects of different pretreatments on its chemical properties and anti-inflammatory activity. Pretreatment of herbal raw materials is an important step which affects the overall quality of Thai traditional medicine. The objectives of this study were to investigate different treatments of C. asiaticum leaves prior to ethanolic extraction and to compare the extracts for their anti-inflammatory activity and chemical properties. The treatments included hot air drying in an oven, microwave drying, traditional grilling on a charcoal stove before drying in an oven, and temperature shock in hot and cold water before hot air drying. The anti-inflammatory activity and chemical properties of the extracts were analyzed using the established methods. Results showed that 95% ethanolic extract of hot air oven-dried leaves had the highest anti-inflammatory activity and total phenolic and lycorine contents. We recommend hot air drying as a preextraction treatment for C. asiaticum leaves for its simplicity, best retention of the herbal quality, and suitability for scaling up to an industrial process.

Effects of household cooking methods on changes of tissue structure, phenolic antioxidant capacity and active component bioaccessibility of quinoa

The effects of four household cooking methods including germination (Ger), baking, normal pressure steaming (NPS) and high pressure steaming (HPS) treatments, on tissue structure, tocopherol, antioxidant capacity and active component (ferulic acid and tocopherol) bioaccessibility of different colored quinoa were investigated. The results showed that Ger increased the phenolic contents and antioxidant capacity, but decreased the contents of tocopherol. The steaming processes destroyed the tissue structure of quinoa to a large extent, causing a significant loss of phenolic/flavonoid components and the resultant decreased antioxidant capacity. The baking process had minimum impact on tissue structure and active components due to the protection of hypocotyl-radicle axis. Besides, through in vitro simulated digestion, Ger improved the bioaccessibility of ferulic acid, and steaming processes increased that of tocopherol. Conclusively, to develop the expected nutritional value of quinoa, several alternative cooking methods are provided according to the respective effects.

Integrated transcriptomic and metabolomic data reveal the flavonoid biosynthesis metabolic pathway in Perilla frutescens (L.) leaves

Perilla frutescens (L.) is an important medicinal and edible plant in China with nutritional and medical uses. The extract from leaves of Perilla frutescens contains flavonoids and volatile oils, which are mainly used in traditional Chinese medicine. In this study, we analyzed the transcriptomic and metabolomic data of the leaves of two Perilla frutescens varieties: JIZI 1 and JIZI 2. A total of 9277 differentially expressed genes and 223 flavonoid metabolites were identified in these varieties. Chrysoeriol, apigenin, malvidin, cyanidin, kaempferol, and their derivatives were abundant in the leaves of Perilla frutescens, which were more than 70% of total flavonoid contents. A total of 77 unigenes encoding 15 enzymes were identified as candidate genes involved in flavonoid biosynthesis in the leaves of Perilla frutescens. High expression of the CHS gene enhances the accumulation of flavonoids in the leaves of Perilla frutescens. Our results provide valuable information on the flavonoid metabolites and candidate genes involved in the flavonoid biosynthesis pathways in the leaves of Perilla frutescens.

Effect of Heat Treatment and Light Exposure on the Antioxidant Activity of Flavonoids

The application of food processes can lead to a modification of both the structure and the activities of flavonoids. In this article, the effect of heat treatment and exposure to light on the antioxidant activity of 6 model flavonoid solutions (rutin, naringin, eriodictyol, mesquitol, luteolin, and luteolin 7-O-glucoside) was studied. The evolution of the antioxidant activity measured after heat treatment of 130 °C at 2 h and an exposure to visible light for 2 weeks is measured by the ABTS (2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) method and represented by a new parameter called ΔTEAC. The model solution of Mesquitol showed the highest increase in ΔTEAC after a heat treatment, a value of 200 mM was obtained. The increase in ΔTEAC is always greater with thermal treatment than with light exposure. Thus, temperature and light lead to different degradation pathways of the flavonoid. In vivo measurements were carried out with solutions of naringin, erodictyol, and luteolin 7-O-glucoside. Heated solutions of flavonoids do not exhibit toxicity on cells. The specific activities of superoxide dismutase and glutathione peroxide have been determined and have shown an increased impact on the potential anti-cancer of these solutions by enhancing their cellular antioxidant activity, as well as modulation of the oxidative stress.

Application of Infrared Heating for Roasting Nuts

Roasting is a key process in production of nuts. Improving the flavor and crispiness of texture in nuts is considered as a purpose of roasting, which increases the overall acceptance of the product. This review aims to introduce the infrared method as a new technique of roasting and evaluate the quality characteristics of some nuts after infrared roasting. Usually, the traditional roasting methods are time-consuming with high energy consumption and low production efficiency. One of the best ways to decrease roasting time and energy consumption is to provide heat by infrared (IR) radiation. However, the low penetration power of infrared radiation is one of the limitations of this method. The combination of infrared with other thermal methods can overcome this limitation. Studies have been done on roasting of nuts and other foods by different IR roasting methods such as IR, IR-hot air, and IR-microwave roasting methods. This paper reviews the effect of different IR roasting methods on the quality characteristics of roasted pistachio, peanut, hazelnut, almond, sunflower, soybean, and other food products. IR heating has been applied successfully to the roasting of some nuts. The use of infrared roasting has several advantages in comparison with traditional convective roasting methods. According to the results of most of these studies, the combination of infrared with other thermal methods to roast nuts has distinctly improved the potential of the technology as compared to the IR roasting alone.

Effects of steam explosion pretreatment on the composition and biological activities of tartary buckwheat bran phenolics

Steam explosion (SE) is an efficient technology to disrupt materials for improving their quality. In this study, SE was applied to release phenolics and improve the roughening of tartary buckwheat bran. The results showed that SE promoted the dissolution of phenolics, particularly, the content of the bound fraction was nearly increased by two times (0.36 vs. 0.99 mg GAE per g DW). The analysis of the phenolic composition showed that SE improved the liberation of bound pyrogallic acid, protocatechuic acid and caffeic acid. The biological activity tests indicated that SE effectively enhanced the oxygen radical absorbance capacity (ORAC) in vitro of the extract of bound phenolics by 270%. It also improved the cellular antioxidant activity (CAA) in vitro of the extract of free phenolics by 215%. Furthermore, SE showed potential in improving the antiproliferative activity of the total phenolic extract against Caco-2 cells as well as the bound phenolic extract against HepG2 cells in vitro.

Thermal Processing for the Release of Phenolic Compounds from Wheat and Oat Bran

The aim of the present paper was to identify the major polyphenolic compounds and investigate the antioxidant, antimutagenic, and antimicrobial activities of industrially-derived cereal byproducts-wheat bran (WB) and oat bran (OB)-before (fresh) and after thermal processing (TP) (10 min, 80 °C), coupled with ultrasound-asssited extraction. The results showed that the thermal process improved the total phenolic content of WB by +22.49%, and of OB with +25.84%. After the TP, the phenolic concentration showed a significant relative percentage increase in the case of WB (ferulic acid +39.18%, vanillic acid +95.68%, apigenin-glucoside +71.96%, p-coumaric acid +71.91) and of OB (avenanthramide 2c +52.17%, dihydroxybenzoic acids +38.55%). The best antioxidant capacity was registered by OBTP followed by WBTP. The strongest antimicrobial inhibition was attributed to the WBTP sample. Both thermally processed matrices had strong antimutagenic activity toward S. typhimurium TA100. This thermal processing was tested on bran based on its practical application within the food industry, considering the design of different cereal byproducts derived from functional foods and nutraceuticals.

Hydrothermal Treatment Enhances Antioxidant Activity and Intestinal Absorption of Rutin in Tartary Buckwheat Flour Extracts

Tartary buckwheat (Fagopyrum esculentum) is widely used in the food industry due to its functionality, which is related to its high rutin content. However, rutin is easily converted into quercetin by an endogenous enzyme during processing, resulting in a bitter taste. In this study, rutin-enriched Tartary buckwheat flour extracts (TBFEs) were obtained by hydrothermal treatments (autoclaving, boiling, and steaming), and their antioxidant activity was evaluated in human intestinal cells. The intestinal absorption of the hydrothermally treated TBFEs was also investigated using in vitro models of intestinal barriers and an ex vivo model of intestinal absorption. The results demonstrated that all of the hydrothermally treated TBFEs had increased rutin, total polyphenol, and total flavonoid contents, which enhance the in vitro and intracellular radical scavenging activities. Antioxidant enzyme activity, cellular uptake efficiency, in vitro intestinal transport efficacy, and ex vivo intestinal absorption of the hydrothermally treated TBFEs were also enhanced compared with those of native TBFE or standard rutin. These findings suggest the promising potential of hydrothermally treated TBFEs for a wide range of applications in the functional food industry.

Alteration of phenolic profiles and antioxidant capacities of common buckwheat and tartary buckwheat produced in China upon thermal processing

BACKGROUND

Buckwheat products are receiving increasing attention because of their high nutritive values and significant health-promoting properties. In the present study, 15 buckwheat products grown in different parts of China were investigated. Representative common or tartary buckwheat samples were further subjected to soaking, roasting, microwave cooking, boiling and steaming treatments. Colorimetric analyses and high-performance liquid chromatography (HPLC) analyses were performed to determine the phenolic profiles and antioxidant capacities of the raw and thermally processed buckwheat samples, respectively.

RESULTS

Tartary buckwheat exhibited a remarkably higher total phenolic content (TPC), total flavonoid content (TFC), 2-diphenyl-1-picryhydrazyl (DPPH) free radical scavenging activity and ferric reducing antioxidant power (FRAP) compared to common buckwheat, although there were no significant differences between their 2,2'-azino-di-(3-ethylbenzthiazoline sulfonic acid) (ABTS) free radical scavenging capacity. All thermal treatments, particularly microwave cooking, contributed to the greatest losses of phenolics and antioxidant capacities in the common buckwheat samples, whereas boiling and steaming usually resulted in the lowest losses. For the tartary buckwheat samples, all thermal treatments (except roasting), especially boiling and steaming, led to significant increases in TPC, TFC, DPPH free radical scavenging activity, FRAP and ABTS free radical scavenging capacity. However, HPLC analyses indicated that all thermal treatments, especially microwave cooking, gave rise to the greatest losses of the total content of 14 phenolic acids and three flavonoids, whereas boiling led to the lowest losses.

CONCLUSION

Both steaming and boiling treatments are recommended when preparing common or tartary buckwheat food products because they can minimize thermal degradation or promote their phenolic compounds and antioxidant capacities to the greatest extent. © 2019 Society of Chemical Industry.

Effect of steam parboiling and hot soaking treatments on milling yield, physical, physicochemical, bioactive and digestibility properties of buckwheat (Fagopyrum esculentum L.)

Post-harvest hydrothermal processing of grains are targeted at improving milling performances and nutritional properties. In this study, the effects of two hydrothermal processes, namely steam parboiling and soaking in boiling water for different durations on properties of buckwheat (Fagopyrum esculentum L.) grown in the Indian Himalayan regions were assessed. Both treatments significantly improved milling yield. Changes in grain section morphology were evidenced under scanning electron microscope. Milder processing for 5 and 10 min mostly exerted annealing effect, represented by increased intensities of X-ray diffraction peaks. Starch gelatinization occurred upon prolonged processing for 15 and 20 min. This resulted in decreased crystallinity, increased sedimentation volume, paste thinning during rapid viscosity analysis and lower thermal transition in differential scanning calorimetry. Marginal changes in oil uptake suggested limited protein denaturation. Natural antioxidant compounds were variably denatured. Maillard browning was indicated by CIE L* a* b* colour and antioxidant levels. The starchy flour samples showed partial resistance to enzymatic amylolysis post retrogradation. Soaking in boiling water can be considered as a feasible alternative to conventional steam parboiling for better milling yield of buckwheat. Altered physicochemical and nutritional properties of buckwheat suggested that the hydrothermally modified flours can be used in ready to eat therapeutic food products.

Comparative study on the phytochemical profiles and cellular antioxidant activity of phenolics extracted from barley malts processed under different roasting temperatures

Consumption of cereal foods has been related to health improvement, which is partly because of their phytochemicals. To explore the functionality and effective application of barley malt, a widely consumed nutritional food, the entire phytochemical profiles and bioactivities of three common barley malt products obtained under different roasting temperatures were analyzed. Results showed that they are abundant in phenolics including flavonoids with high antioxidative activities, as displayed by cellular antioxidant activity (CAA), oxygen radical absorbance capacity, peroxyl radical scavenging capacity, and DPPH and ABTS radical scavenging assays. Among the three barley malts, the raw barley malt bound extract and the dark barley malt free extract exhibited higher CAA values, while the raw barley malt contained a negligible amount of bound phenolics. An efficacious antiproliferation capacity of the dark barley malt free extract was detected in Caco-2 cells. Results also provide an insight into the positive attributes of thermal processing for the biofunctionality of barley malts, especially through the tuning of the accessibility and variability of beneficial phytochemicals.