Comparative analyses of phenolic composition, antioxidant capacity, and color of cool season legumes and other selected food legumes

ABSTRACT:  The objective of this study was to characterize the phenolic compounds and antioxidant activities of U.S.-produced cool season legumes. A total of 33 cool season legume samples were selected. Some common beans and soybeans were included for comparisons. Total phenolic content (TPC), total flavonoid content (TFC), and condensed tannin content (CTC) were analyzed. Ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, and oxygen radical absorbance capacity (ORAC) were used for analyzing antioxidant properties. Color of the legume flour and the seed coat was also analyzed. TPC, TFC, CTC, FRAP, DPPH, and ORAC values of legumes were significantly different not only between classes but also among samples within each class. Among cool season legume classes, lentils possessed the highest concentrations of the phenolic compounds and antioxidant activities. Colored common beans and black soybeans exhibited higher TPC, TFC, CTC, FRAP, DPPH, and ORAC values than those of yellow peas, green peas, and chickpeas. Antioxidant activities (FRAP, DPPH, and ORAC) were strongly correlated ( r = 0.96, 0.94, and 0.89, respectively, P < 0.01) with TPC. TPC and ORAC were moderately correlated ( P < 0.01) with either the seed hull surface color or the flour color.     

A comprehensive study of polyphenols contents and antioxidant potential of 39 widely used spices and food condiments

Spices and condiments are rich sources of potent antioxidants. In the present investigation, total equivalent antioxidant capacities (TEAC) of 39 spices were studied using 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) scavenging, and cupric reducing antioxidant capacity (CUPRAC) assays. Their total phenolic contents (TPC) and total flavonoid contents (TFC) were also determined. TEAC, TPC, and TFC varied significantly (P?<?0.05) among these spices. ABTS, DPPH, and CUPRAC assay values of studied spices ranged from 1.42 to 112.94 mg ascorbic acid equivalents (AAE)/g, 1.14 to 91.09 mg Trolox equivalents (TE)/g, and 0.52 to 54.47 mg TE/g, respectively (dry weight basis; DW). Based on Folin–Ciocalteu assay, TPC ranged from 2.93 to 160.55 mg of gallic acid equivalents (GAE)/g DW. Strong correlations between TPC and TEAC values (R?=?0.966, 0.825, and 0.954 for ABTS, DPPH, and CUPRAC, respectively) were found. This indicates that phenolic compounds are potent antioxidants in these spices. Principal component analysis (PCA) indicated that cloves (flower buds of Syzygium aromaticum) had the most distinct and potent antioxidant capacity, followed by allspice (fruits of Pimenta dioica) and cinnamon (bark of Cinnamomum verum). Results of the present study provide adequate evidence that polyphenols are responsible for their compelling antioxidant capacities of studied spices. Thus, consumption of antioxidant-rich spices such as cloves, allspice, and cinnamon can significantly prevent oxidative stress in the human body.     

Evaluation of antioxidant activities and total phenolic contents of typical malting barley varieties

Fourteen typical malting barley varieties from China were evaluated for their DPPH radical, ABTS radical cation and superoxide anion radical scavenging activities, reducing power, metal chelating activities, and total phenolic contents (TPC). All barley samples exhibited significant antioxidant activities determined by different assays, and contained significant levels of phenolic compounds. Gan4 and Wupi1 barley exhibited the highest DPPH radical scavenging activity, ABTS radical cation scavenging activity and reducing power. Gan4 and Humai16 barley showed the highest TPC, whereas the highest superoxide anion radical scavenging activity and metal chelating activity were found in Huaimai19 and Ken3 barley, respectively. The Pearson correlation analysis revealed that the TPC showed strong correlations with DPPH radical scavenging activity, ABTS radical cation scavenging activity, and reducing power (P < 0.01), whereas its correlations with superoxide anion radical scavenging activity and metal chelating activity were poor (P > 0.05). Moreover, DPPH radical scavenging activity, ABTS radical cation scavenging activity and reducing power were well positively correlated with each other (P < 0.01). Principal component analysis (PCA) was applied to understand the interrelationships among the measured antioxidant activity evaluation indices, and to gain an overview of the similarities and differences among the 14 barley varieties.     

丝瓜花不同溶剂提取物抗氧化活性及其酚类成分分析

以无水乙醇、70%乙醇、40%乙醇和水分别对丝瓜花进行提取,并测定各提取物中总酚、总黄酮含量,采用DPPH·清除能力、超氧化物自由基清除能力、FRAP抗氧化能力和亚铁离子螯合能力等方法评价其抗氧化活性,通过HPLC分析其中酚类成分。结果表明,70%和40%乙醇提取物总酚及总黄酮含量较高,而且DPPH·清除活性、FRAP还原力最强,40%乙醇提取物、水提物分别具有最强的超氧阴离子自由基清除活性和亚铁离子螯合能力。总酚含量与DPPH·清除活性之间存在较强的相关性(R²=0.8688)。HPLC分析检出提取物中9种酚类化合物,其中含量最高的为杨梅素。试验结果说明,70%乙醇、40%乙醇可能是丝瓜花抗氧化性物质提取的较好溶剂。结果表明丝瓜花是一种较好的抗氧剂资源。     

Characterisation and comparison of phenols,flavonoids and isoflavones of soymilk and their correlations with antioxidant activity

To investigate the relationship between bioactive compounds and antioxidant property, total phenolic content (TPC), total flavonoid content (TFC), individual and total isoflavone content of soymilk and their correlations with oxygen‐radical‐absorbing capacity (ORAC), ferric reducing antioxidant power (FRAP) and 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging capacity values were evaluated and compared. Results showed that TPC, TFC, isoflavones (including concentration and profiles) and antioxidation activity significantly varied among ten tested soybean cultivars. Significant correlations were established between DPPH and TFC (r = 0.553, P < 0.01), DPPH and TPC (r = 0.753, P < 0.01), FRAP and TFC (r = 0.599, P < 0.01) and FRAP and TPC (r = 0.616, P < 0.01). Positive linear correlations were found between subtotal, total isoflavones and ORAC. Unlike other isoflavone monomers, aglycone isoflavones correlated positively with DPPH and FRAP significantly. DPPH well correlated with FRAP, whereas neither DPPH nor FRAP correlated with ORAC. TPC, TFC, individual and total isoflavone values are potentially useful for soymilk antioxidant activity assessment.     

Ultrasound-assisted extraction and antioxidant activity of phenolic and flavonoid compounds and ascorbic acid from rugosa rose (<Emphasis Type="Italic">Rosa rugosa</Emphasis> Thunb.) fruit

The present study aimed to extract total phenolic compounds (TPC), total flavonoid compounds (TFC), and ascorbic acid (AA) from the fruit of rugosa rose (Rosa rugosa Thunb.) by ultrasound-assisted extraction (UAE), and to evaluate their antioxidant activities. UAE significantly increased the extract yield compared with that obtained using the conventional method. TPC, TFC, and AA were extracted, depending on the extraction conditions (temperature, time, and ethanol concentration), in the range of 50.73–96.69, 15.93–31.88, and 3.06–6.08 mg/g, respectively. TPC and TFC were effectively extracted at a relatively high temperature (50 °C) than AA was (30 °C). The solvent condition used to extract TPC, TFC, and AA was 50% ethanol. The UAE condition for the highest antioxidant activity was obtained 30 °C, 30 min, and 50% ethanol, which were the same condition for the highest AA extraction. Among the extracts, AA showed a strong correlation with antioxidant activity at p-value of 0.001.     

Changes in the phenolic compounds and antioxidant activities of mustard leaf (<Emphasis Type="Italic">Brassica juncea</Emphasis>) kimchi extracts during different fermentation periods

This study was conducted to investigate the changes in the total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activities of 80% methanol and water extracts from mustard leaf kimchi during different fermentation periods. The methanol extract exhibited higher TPC and TFC than the water extract. Both extracts from kimchi fermented for two months showed the highest antioxidant effects against the scavenging activities of 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radicals and 2,2-azino-bis diammonium salt (ABTS) radicals. Moreover, the methanol extract from kimchi fermented for two months showed the highest nitrite scavenging activity. The highest metal (Fe²⁺) chelating effect of the methanol extract and water extract was observed after three months and one month, respectively. Caffeic acid showed the highest increase with fermentation. These findings suggest that the antioxidant activities of kimchi depend on the fermentation period. Accordingly, this study provides basic data for improving the antioxidant activity of mustard leaf kimchi through the establishment of their fermentation period.     

Antioxidant and Free Radical Scavenging Capacity of Extensively Used Medicinal Plants in Sri Lanka

The burden of chronic diseases is rapidly increasing worldwide. Diet and nutrition are important factors in the promotion and maintenance of good health throughout the entire life course. Physiological and biochemical alterations in the human body may result in overproduction of free radicals leading to oxidative damage to biomolecules (e.g. lipids, proteins, DNA). Use of medicinal plant based products has increased recently because of their exerted beneficial properties such as antioxidant, anticancer, hypoglycaemic and hypolipidaemic activities. The present study was designed to assess the in vitro antioxidant activity and free radical scavenging capacity of ten medicinal plants which are extensively used in the Ayurvedic treatment systems in Sri Lanka. Water extracts were prepared and evaluated for their free-radical scavenging capacity and antioxidant activity using a number of chemical assays; DPPH, ABTS and FRAP. The total Phenolic (TPC) and Total Flavonoid Content (TFC) were also assessed. The TPC and TFC values of the extracts varied from 295.94±3.65 – 5.22±0.08 (mg Gallic Acid Equivalent (GAE)/g dry weight) and 115.01±1.69 – 0.97±0.002 (mg Catechin Equivalent (CE)/g dry weight) respectively. The DPPH and ABTS radical scavenging activities were higher for the Nelli (Phyllanthus emblica) extract while the least activity was observed in Venivel (Cosciniumfenestratum) extract. The FRAP activity of the extracts was well proved with the DPPH and ABTS radical scavenging activities. A positive, significant linear relationship between antioxidant activity and TPC and TFC content showed that phenolic compounds and flavonoids were the dominant antioxidant components in the medicinal herbs studied.     

Antioxidant potential of wheat flour chapattis as affected by incorporating barley flour

Whole wheat flour was replaced with whole barley flour at levels of 28, 56 and 84 g/100 g to prepare chapattis and their antioxidant properties were evaluated before and after baking. The total phenolic content (TPC) in wheat flour was 2062 μg ferulic acid equivalents/g, total flavonoid content (TFC) was 966 μg catechin equivalents/g and antioxidant activity was 12.3% and they increased by 57.1, 101 and 22.6%, respectively upon incorporating barley flour at the highest level. Baking significantly decreased the TPC by up to 17.0% and TFC by up to 30.7% however the AOA increased by 13%. Barley flour incorporation significantly increased the reducing power which upon baking showed an insignificant decrease. Polyphenol oxidase (PPO) activity significantly increased by up to 109% upon incorporating barley flour however baking lowered PPO activity by 67.9%. Chapattis containing barley flour can be used to deliver the bioactive components of barley.     

Changes of heat-treated soymilks in bioactive compounds and their antioxidant activities under in vitro gastrointestinal digestion

To investigate the influence of in vitro gastrointestinal digestion on contents of bioactive compounds and antioxidant activities of heat-treated soymilks, changes of total phenolics content (TPC), total flavonoids content (TFC), content and profile of isoflavones, oxygen radical absorbance capacity (ORAC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and ferric-reducing antioxidant power (FRAP) were assayed after different heat treatments (at 95 °C for 20, 40, 60 min; 121 °C for 3, 6, 9 min and 143 °C for 20, 40, 60 s respectively) and gastrointestinal digestion. Results showed that digestion significantly influenced the contents of bioactive compounds and antioxidant activities of soymilks. Increases of DPPH radical scavenging activity, FRAP and ORAC of the heat-treated soymilks after gastric digestion were consistent with the increases of TPC (110.68–152.60 %) and TFC (4.48–31.10 %). In the dialysate fractions as the absorbable and utilized part, it was found that TPC, TFC, isoflavones and antioxidant activities (DPPH radical scavenging activity, FRAP and ORAC) were significantly decreased as compared with the gastric digestion fractions and duodenal fractions. Analysis showed that the bioaccessibility of TPC reached 107.17–125.14 %, TFC reached 34.63–67.19 % and total isoflavones reached 34.40–41.22 %, respectively, indicating the rich bioaccessible compounds in soymilk. Daidzein and its derivates were proven as the most bioaccessible isoflavones (about 36.99–44.14 %). Glucoside isoflavones showed the highest bioaccessibilities followed by malonylglucosides, acetylglucosides and aglycones. Overall, the soymilks treated at 95 °C and 60 min and 121 °C and 9 min had higher bioactive compounds contents, antioxidant activities and bioaccessibilities in the dialysate fractions.     

Phenolic Profiles and Antioxidant Capacities of Chinese Unifloral Honeys from Different Botanical and Geographical Sources

Honey has been acknowledged worldwide as a good source of natural antioxidants. Chemical properties of total phenolics and flavonoids of 33 Chinese unifloral honeys from nine different floral sources were investigated. Antioxidant activities including 1, 1-diphenyl-2- picrylhydrazyl radical (DPPH·) scavenging, superoxide anion radical (O₂ ^?·) scavenging, hydroxyl radical (·OH)-scavenging activities, and reducing powers were evaluated. The results indicated that total phenolic content (TPC) ranged from 10.43 to 149.6 mg of PCE/100 g, while total flavonoid content (TFC) ranged from 9.41 to 102.1 mg QE/100 g. Positive correlations between radical-scavenging activities and, respectively, TPC values and TFC values were found. Remarkable variations in antioxidant properties, TPC, and TFC values were demonstrated in hydrophilic extracts of honeys from different botanic and/or geographic sources. The current findings will provide useful information for evaluating the food quality of Chinese honey and for educating consumers to choose specific honey lines for their specific health-promoting effects.     

Cookie making behavior of wheat–barley flour blends and effects on antioxidant properties

Refined wheat flour was replaced with whole barley flour at varying levels and the blends were evaluated for their cookie making behavior. The spread factor of cookies decreased as the proportion of barley flour increased while snap force and water activity increased significantly upto 114.7 N and 0.397 in only barley flour cookies. Increasing levels of barley flour lead to a significant decrease in L^∗ and b^∗ values of cookie dough. Peak viscosity (PV) and final viscosity (FV) increased significantly as the levels of barley flour increased. A significant increase in antioxidant activity (AOA), total phenolic content (TPC), metal chelating activity (MCA), reducing power (RP) and total flavonoid content (TFC) was observed as the proportion of barley flour increased. Baking lead to a significant decrease in TPC and TFC whereas AOA, MCA and RP increased. Baking lead to a significant increase in the non-enzymatic browning index of cookies.     

Influence of heating on the polyphenolic content and antioxidant activity of grape seed flour

Abstract: The production of grape seed flour (GSF) from a waste product generated during winemaking, is of interest in product development applications due to its potential health benefits. However, before GSF can used in baking as a source of additional antioxidants, research on its heat stability is required. The overall objective of this study was to assess changes in phenolic content and antioxidant activity of GSF during heating. Merlot GSF was heated at 5 temperatures (120 to 240 °C) for 0 to 90 min. At each time/temperature combination, total phenolic content (TPC), total flavanoid content (TFC), Trolox equivalent antioxidant capacity (TEAC), 2,2 diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging, and ferric ion reducing antioxidant power (FRAP) of the extracts were determined. Specific polyphenolic compounds, including catechin, gallocatechin, epicatechin, and gallic acid were also measured. Results showed that when Merlot GSF was heated to ≥180 °C, significant decreases in the TPC and antioxidant activity, measured using FRAP, DPPH, and TEAC, were observed. Longer heating times also caused a reduction in antioxidant capability. Catechin and epicatechin content decreased with increasing heating temperature while gallocatechin and gallic acid content increased. Both catechin and epicatechin content had strong positive correlations (r > 0.91) with TPC and TFC, as well with FRAP and TEAC, suggesting that the GSF antioxidant activity is related to the presence of these particular compounds. Overall, while a decrease in antioxidant content was observed during heating, this occurred at higher baking temperatures. Thus GSF may be suitable for use as an ingredient in baked goods to bolster antioxidant content. Practical Application: In order for Merlot grape seed flour (GSF) to be used in baking as a source of additional antioxidant compounds, the impact of heating on the polyphenolic compounds in the GSF needed to be examined. Thermal treatment of Merlot GSF caused significant decreases in the TPC, antioxidant power, and specific polyphenolic compounds when heated ≥180 °C. Thus while antioxidant content decreased with higher heating temperatures, this occurred at higher baking temperatures. Thus, GSF may be suitable for use as an ingredient in baked goods to bolster antioxidant content.     

A comparative study on phenolic profiles and antioxidant activities of legumes as affected by extraction solvents

ABSTRACT:  The objective of this study was to investigate how 6 commonly used solvent systems affected the yields of phenolic substances and the antioxidant capacity of extracts from 8 major classes of food legumes. Several antioxidant-related phytochemical compositions, namely, total phenolic content (TPC), total flavonoids content (TFC), and condensed tannins content (CTC), were investigated. In addition, antioxidant activities were tested using 2,2-diphenyl-1-picryhydrazyl (DPPH) free radical scavenging, ferric-reducing antioxidant power (FRAP), and the oxygen radical absorbance capacity (ORAC). The results showed that the 50% acetone extracts exhibited the highest TPC for yellow pea, green pea, chickpea, and yellow soybean. Acidic 70% acetone (+0.5% acetic acid) extracts exhibited the highest TPC, TFC, and FRAP values for black bean, lentil, black soybean, and red kidney bean. The 80% acetone extracts exhibited the highest TFC, CTC, and DPPH-free radical scavenging activity for yellow pea, green pea, chickpea, and yellow soybean. The 70% ethanol extracts exhibited the greatest ORAC value for all selected legumes. These results indicated that solvents with different polarity had significant effects on total phenolic contents, extracted components, and antioxidant activities. High correlations between phenolic compositions and antioxidant activities of legume extracts were observed. The information is of interest to the nutraceutical food/ingredient industries since legumes are a rich source of antioxidants.     

Influence of germination period on physicochemical,pasting and antioxidant properties of Indian wheat cultivars

In the present study, physicochemical, pasting and antioxidant properties of six wheat (Triticum aestivum L.) cultivar grains after 24, 48 and 72 h of germination duration were evaluated and compared with their un-germinated counterparts. Chemical compositions of un-germinated fraction of whole flour were also determined. The results showed that swelling power decreased whereas solubility increased as the time of germination increased. From 24 to 72 h water and oil absorption capacities increased significantly with germination. The DPPH radical scavenging activity and reducing power exhibited significant (p?≤?0.05) increase with germination for all the cultivars. Total phenolic content ranged from 463.6 to 644.6 µg ferulic acid equivalents (FAE)/g for un-germinated to 1255.5–2380.9 µg FAE/g for germinated whole grain flour. Total flavonoids content increased from 86.5 to 266.7 µg catechin equivalents (CE)/g for un-germinated to 289.7–385.4 µg CE/g as the duration of germination increased from 0 to 72 h. The characteristics curves showing pasting profile of different cultivars became nearly linear for 48 and 72 h germinated grain flour. Several, significant correlations were observed among studied properties from principal component analysis.     

Bioaccessibility and antioxidant potential of millet grain phenolics as affected by simulated in vitro digestion and microbial fermentation

Dehulled and cooked grains of five millet varieties (kodo, finger, proso, foxtail and pearl) were subjected to in vitro enzymatic digestion and microbial fermentation under physiological conditions in order to determine the bioaccessibility of their phenolic compounds. Extracts recovered as supernatants from enzymatic digestion and microbial fermentation were employed for the determination of their total phenolic content (TPC) and total flavonoid content (TFC), as well as the scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH), peroxyl and hydroxyl radicals. Furthermore, trolox equivalent antioxidant capacity (TEAC), reducing power and ferrous ion chelating activity of the extracts so obtained were evaluated. The DPPH and hydroxyl radical scavenging activities were determined using electron paramagnetic resonance (EPR) spectroscopy. The peroxyl radical activity was measured using an oxygen radical absorbance capacity (ORAC) assay. The TPC ranged from 12.7 to 35.4 and 21.2 to 47.4 μmol ferulic acid equivalents per gram of grain, on a dry weight (dw) basis at the end of intestinal digestion and colonic fermentation, respectively. All five millet varieties exhibited effective antioxidant activity and the order of efficacy differed according to the assay employed. The present study thus demonstrated that phenolic compounds of processed millets were bioaccessible and colonic fermentation released the phenolics bound to the insoluble fibre in the grain.     

Antioxidant and Anti-diabetic Properties of Caryota Urens (Kithul) Flour

Starch extracted from pith of Caryota urens L. (Family: Arecaceae) palm is known as “Kithul flour” and is claimed to have health benefits according to folklore and Ayurveda. Antioxidants are believed to possess numerous health benefits. However, as yet, health benefits of C. urens flour have not been scientifically investigated. Antioxidant properties of C. urens flour were tested using different in vitro assays namely, 2,2-azino-bis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS⁺), ferric reducing antioxidant power, oxygen radical absorbance capacity and ferrous ion chelating assays. Total Phenolic Content (TPC) and Total Flavonoid Content (TFC) were also evaluated. Anti-diabetic properties were estimated using alpha amylase and alpha glucosidase enzyme inhibition assays. Dried methanolic extracts of both boiled and raw samples were used in all assays. Results of the study showed that C. urens flour possess free radical scavenging activity(raw 0.02± 0.01 and boiled 0.04±0.01 mg trolox equivalent (TE)/ g flour), electron donating reducing power (raw 0.10±0.03 and boiled 0.36±0.11 mg TE/g flour), oxygen radical absorbance capacity (raw 2.29± 0.71 and boiled 192.3 ± 57.71 mg TE/1 g flour) and metal ion chelating capacity (raw 0.03±0.01 and boiled 0.14±0.04 mg EDTA equivalents /g flour) exhibiting its antioxidant potential. TPC (raw 1.1±0.3 and boiled 5.12 ± 1.89 mg GAE/g flour) and TFC (raw 1.65 ± 0.47 and boiled 6.69 ± 1.27 μg QE/g flour) which are said to be contributed to antioxidant activities were also found. In addition, boiled flour which is generally consumed as a food has shown higher antioxidant activity. Caryota urens flour did not contain marked anti-diabetic properties. It is evident from results that Caryota urens flour has moderate antioxidant property which may associate with its traditional health claims.     

Physicochemical properties,antioxidant activity and cellular protective effects of honeys from southern Africa

The southern Africa region is a region of unique floral biodiversity; this study was undertaken to address the limited knowledge regarding the physiochemical, antioxidant activity and the ability of these honeys to protect biomolecules and cells against oxidative damage. The physicochemical properties, total polyphenolic and flavonoid content (TPC and TFC), catalase and antioxidant activity (DPPH, TEAC, and ORAC assays) of 13 representative honey samples was determined. Biological and cellular protection was investigated using the erythrocyte haemolysis, the pBR322 plasmid, as well as the dichlorofluorescein diacetate (DCFH-DA) assays in SC-1 and Caco-2 cells. High TPC, TFC, catalase and antioxidant activity was obtained, and all honeys protected DNA, erythrocytes and cells in vitro. Colour, TPC, TFC and antioxidant activity correlated well but no correlation was seen between these parameters and catalase activity, biological and cellular effects. Nevertheless, honeys with high catalase activity and/or are dark in colour with high TPC, TFC and/or antioxidant activity did show the highest degree of biological and cellular protection.     

Comparing impacts of dielectric barrier discharge plasma and electron beam irradiation processing on characteristics of Tartary buckwheat whole flour

Dielectric barrier discharge (DBD) plasma, lower and higher dose electron beam irradiation (EBI) are used widely in food processing. In this research, impacts of DBD plasma and EBI processing on characteristics of Tartary buckwheat whole flour were investigated in the range of parameters used most often in food industry. Cross section, small granule and reaggregation of fragments appeared after processing as well as higher values of L*, a* and WI. DBD plasma processing altered the short range crystal structure and hydrogen-containing groups, increasing oil/water absorption and freeze-thaw stability. DBD plasma and EBI processing had a mostly positive effect on hydration properties at 50 to 70 °C, with contrast to a reduction effect at higher temperature. DBD plasma and EBI processing will not affect the nutrients content indeed. TPC, TFC and antioxidant activity increased significantly after EBI processing (≤ 10 kGy) with few free radicals generated.Industrial relevanceDBD plasma and EBI processing are widely used for flour in food industry, with limited focus on physicochemical properties promotion and antioxidant activity protection. This research indicates that DBD plasma processing can affect the properties of Tartary buckwheat whole flour (TBF) significantly, but it shows negative damage to bioactive compounds and antioxidant activity. EBI processing (≤ 10 kGy) can improve physicochemical properties of TBF, which is given slightly higher TPC, TFC and antioxidant activity simultaneously. Both of DBD plasma and EBI processing are safe methods that can improve processing characteristics of the flour, while lower dose EBI processing is more suitable for development of Tartary buckwheat and functional food industry with protection to bioactive compounds and antioxidant activity.     

蓝莓花、茎、叶酚类物质含量及抗氧化活性比较

比较蓝莓花、嫩茎、嫩叶及老叶总多酚、总黄酮、原花青素的含量,并研究其抗氧化性能差异。结果表明:嫩叶中总多酚含量最高,为43.77 mg GAE/g(以干质量计,下同),分别是花、嫩茎和老叶的3.45、1.42、1.12倍;老叶中总黄酮、原花青素含量最高,为68.01 mg RE/g、23.29 mg CAE/g,分别是花的2.57倍和4.61倍、嫩茎的1.79倍和1.23倍、嫩叶的1.03倍和1.98倍。抗氧化性能中,老叶的铁还原能力最大,其次是嫩茎和花,嫩叶较差;清除·OH的能力为嫩茎嫩叶花老叶;清除DPPH自由基能力和总抗氧化能力均为嫩茎嫩叶老叶花甲醇提取物,均高于对照品;蓝莓各部分提取物对DPPH自由基的清除能力最强,总抗氧化能力次之,清除·OH能力和铁还原能力较差。