Dynamic changes in phytochemical composition and antioxidant capacity in green and black mung bean (Vigna radiata) sprouts

The mung bean (Vigna radiata) sprout is a popular fresh vegetable in many parts of the world. In this study, the dynamic change of ascorbic acid, phenolic composition and antioxidant capacity were evaluated in green and black mung bean sprouts. Germination increased ascorbic acid, total phenolic content and antioxidant capacity in both mung beans. The green mung bean sprout generally had higher ascorbic acid, total phenolic content and antioxidant capacity than the black mung bean sprout. Most phenolic compounds, such as caffeic acid, catechin, ferulic acid, gallic acid and rutin, were found to gradually increase after germination. Therefore, mung bean sprouts, especially green mung bean sprout possessing high level of antioxidant phytochemicals, can be valuable functional vegetables and good sources of natural antioxidants.     

Effects of UV‐B on vitamin C,phenolics, flavonoids and their related enzyme activities in mung bean sprouts (Vigna radiata)

In this study, ultraviolet‐B radiation (UV‐B) was used to effect the accumulation of vitamin C, phenolics and flavonoids in mung bean sprouts. Results indicate that the content of vitamin C and flavonoids increased during the initial period, and after a brief decline, reached peak levels of 25.29 ± 1.02 mg/100 g FW and 726.67 ± 7.35 mg/100 g DW, respectively, at 2.5 h (1.845 kJ m^?2), while the peak levels of the phenolics were 10741.33 ± 68.04 mg/100 g DW. The thiobarbituric acid reactive substances (TBARS) content decreases with the increase in irradiation time. The activities of the related enzymes, including phenylalanine ammonia‐lyase (PAL), L‐galactono‐1, 4‐lactone dehydrogenase (GalLDH), peroxidase (POD), polyphenol oxidase (PPO) and chalcone isomerase (CHI) were determined, which showed strong correlations with the change in the content of vitamin C, phenolics and flavonoids. In conclusion, the accumulation of vitamin C, phenolics and flavonoids in mung bean sprouts can be promoted by a low‐dose UV‐B irradiation.     

A comparative study of physico‐chemical properties and antioxidant activity of freeze‐dried mung bean (Vigna radiata) and adzuki bean (Vigna angularis) sprout hydrolysate powders

Mung bean (MB) and adzuki bean (AZB) sprouts were hydrolysed with Flavourzyme^® at four different concentrations for 6 h. Nongerminated beans subjected to each enzyme concentrations were set as the control. For both bean sprouts, the highest amounts of free amino group, total free amino acids and total phenolic content (TPC) were obtained with 7% (w/w) Flavourzyme^®. Each bean sprout hydrolysate was subjected to freeze‐drying in absence and presence of 5% maltodextrin (w/v). The addition of maltodextrin resulted in a decrease in the free amino group, TPC, surface hydrophobicity and hygroscopicity in resulting freeze‐dried powders. Gallic acid, p‐coumaric acid and vitexin were identified in all freeze‐dried powders, while catechin and rutin were detected only in freeze‐dried AZB hydrolysate powder. Freeze‐dried AZB hydrolysate powder contained higher antioxidant activities. DPPH radical scavenging activity of all samples measured using electron spin resonance spectrometry was higher than that obtained by the colorimetric method.     

Functional properties of 8S globulin fractions from 15 mung bean (Vigna radiata (L.) Wilczek) cultivars

The functional properties including solubility, water absorption capacity, oil absorption capacity, foaming properties and emulsifying properties of 8S globulin fractions from 15 mung bean cultivars were investigated in this study. In addition, the effects of pH on solubility, foaming properties and emulsifying properties were studied. The functional properties of the 8S globulin fractions varied significantly among the different mung bean varieties and exhibited better performance in solubility and emulsion stability compared with soya bean 7S protein. A negative correlation was found between water absorption capacity and oil absorption capacity. Remarkable differences in polypeptides constituents were observed in 8S globulin fractions, and the ratio of 11S/8S globulins has a positive effect on water absorption capacity while a negative effect on oil absorption capacity. As a function of pH, the emulsifying activity indexes of the 8S globulin fractions were found to be distinctly dependent on the solubility, while no significant correlation was found between the emulsifying stability and solubility, nor between the foaming properties and solubility. The foaming capacity showed a strong correlation with foam stability.     

Hypolipidemic and hypoglycemic potential of raw,boiled, and sprouted mung beans (Vigna radiata L. Wilczek) in rats

This study was carried out to investigate the hypolipidemic and hypoglycemic potential of raw, boiled, and sprouted mung beans in rats. Oven dried mung bean powders; raw, sprouted, and boiled were included at 30% level in the diet of seven weeks old male Wistar rats maintained for 5 weeks on high (0.5%) cholesterol diet in comparison with control diet. Low serum glucose and triglyceride concentrations (p < .05) in raw and processed mung bean diets fed rats were supported by low serum insulin level in both raw mung bean diet and boiled mung bean diet fed rats. Hypoglycemic effect in sprouted mung bean fed rats was supported by higher α‐amylase inhibitory activity and α‐glucosidase inhibitory activity of sprouted mung beans. Increase in serum non‐HDL cholesterol concentration and decrease in HDL cholesterol concentration caused by high cholesterol diet were modulated (p < .05) by both boiled and sprouted mung bean diets.

Practical applications

Mung bean is a green legume rich in protein, fiber, antioxidants, and phytonutrients. Hypocholesterolemic and hypoglycemic potential of raw mung beans have been shown previously. It is well known that cooking and processing modulate nutritional and biochemical parameters of foods. However, very limited information is available on the effect of processing on functional properties of legumes. Results of this study showed that boiling and sprouting improved the soluble fiber content and hypocholesterolemic potential of mung beans. Thus, the processed mung beans may be more suitable for developing food supplements for patients with hypercholesterolemia.     

Effect of ochratoxin A on some biochemical changes in seeds of mung bean (Vigna radiata,var Pusa 119

The effect has been studied of a range of concentrations of ochratoxin A on some biochemical parameters, viz chlorophyll, protein and nucleic acid concentrations during seed germination and seedling growth in mung beans (Vigna radiata (L) Wilczek, var Pusa 119). Reduction in levels of all the parameters resulted from ochratoxin A treatment, and the extent of reduction was directly influenced by the concentration of toxin applied.     

外源锌浸种处理对绿豆芽生长和营养品质的影响

为开发一种富锌食品,采用不同浓度硫酸锌(0²00 mg Zn²⁺/L)溶液浸泡绿豆种子8 h并水培96 h后,研究外源锌浸种对绿豆芽生长指标、主要营养成分、植酸及锌积累的影响。结果显示:25⁷5 mg Zn²⁺/L锌溶液浸种可以提高绿豆芽下胚轴长、根长、生物产量和主要营养成分的含量,其中以50 mg Zn²⁺/L最显著,该浓度锌溶液浸种后培育的绿豆芽中游离氨基酸总量、维生素C、可溶性蛋白、可溶性糖的含量分别达到8.96 mg/g、23.76 mg/100 g、56.82 mg/g、6.62 mg/g;在实验考察的浓度范围内,绿豆芽中锌含量增加了90.9%⁶17.0%;萌发和外源锌浸种分别使植酸含量降低了61.5%和62.0%,但两组间无显著差异（p>0.05）。本研究表明,适当浓度的外源锌(<75 mg Zn²⁺/L)浸种处理对绿豆的萌发和生长是有利的,不仅能增加微量元素锌的营养价值,同时又能提高绿豆芽的营养品质。      

The effects of blackcurrant powder (Ribes nigrum) supplementation on pasting properties,physicochemical properties,and nutritive values of starch derived from mung bean (Vigna radiata L.) and pea (Pisum sativum L.)

Incorporation of bioactive-containing fruits and/or vegetables into the carbohydrate-rich food matrix are effective strategies to develop food products with functional health benefits. In this study, blackcurrant powder was added into pea starch and mung bean starch to form pastes to investigate the effects of blackcurrant powder on physicochemical and nutritional properties of the starch pastes. The predictive in vitro glycaemic response of the pastes was highlighted by in vitro glycaemic glucose equivalent assay and alpha-amylase inhibitory activity assay. Both assays showed that blackcurrant powder attenuated (P < 0.05) reducing sugar released, through the inhibition of α-amylase. The colour profiles and textural properties of the pastes were modified by the additions of blackcurrant berry powder at different levels. Nutritional characteristics of the pastes, including total phenolic content and antioxidant activity, were significantly changed (P < 0.05) with the addition of blackcurrant powder.     

绿豆萌发过程中绿豆蛋白的功能特性及其抗氧化性

本文以绿豆为材料,研究了其萌发过程中绿豆蛋白的功能特性(溶解性、持水性、持油性、乳化性、起泡性、乳化稳定性、起泡稳定性)及抗氧化性(DPPH自由基清除率、金属离子螯合率、超氧阴离子自由基清除率)的动态变化。结果表明,随着萌发时间的不断延长,绿豆蛋白的溶解性、持水性、持油性、乳化性、起泡性均呈现先增加后降低的趋势,乳化稳定性和起泡稳定性得以增强。其中,溶解性萌发24 h时达到最高,萌发96 h最低;萌发的绿豆蛋白持水性、持油性和乳化性相对于未萌发的分别提高了1.57倍、4.13倍和2.47倍;乳化稳定性、起泡性和起泡稳定性较未萌发的分别提高了43.8%、46.6%和61.3%。此外,萌发过程中的绿豆蛋白抗氧化性呈现先升高后下降的趋势,萌发促进了绿豆蛋白的抗氧化性。其中,DPPH自由基清除率和金属离子螯合率均在绿豆萌发36 h达到最大,较未萌发的分别提高了73.8%和31.0%;超氧阴离子自由基清除率萌发48 h达到最大,较未萌发的提高了81.7%。随着绿豆萌发时间的延长,绿豆蛋白的功能特性和抗氧化性呈现先升高后下降的趋势,萌发中期(24~48 h)达到最大。因此,萌发提升了绿豆蛋白的功能特性和抗氧化性,扩大了其在食品加工中的应用,提高了其利用价值。     

绿豆抗氧化活性肽的分离纯化及其组成分析

采用超滤法和Sephadex G-25凝胶色谱法对绿豆蛋白的酶解产物进行了分离纯化,得到了分子量为3426和1272u的两种绿豆抗氧化活性肽T1和T2,T1的纯度为85.92%,T2的纯度为94.99%,T1和T2均含有16种相同的氨基酸,表现出较强的体外抗氧化能力,T1对羟自由基和DPPH自由基的清除率分别为69.14%和58.62%;T2对羟自由基和DPPH自由基的清除率分别为91.70%和74.68%。      

绿豆多酚提取工艺优化及抗氧化活性研究

采用溶剂浸提法对绿豆中多酚进行提取,研究液料比、提取时间及提取温度对绿豆多酚提取量的影响,优化了绿豆多酚的提取工艺,并研究了提取液的抗氧化活性。结果表明:最优提取工艺为提取料液比112(g/mL)、提取温度46℃、提取时间1.6h。该条件下多酚提取量为11.74mg/g。最佳工艺得到的提取液对超氧阴离子自由基清除率为58.5%,亚硝酸根离子清除率为26.0%,表明绿豆多酚具有良好的抗氧化活性。     

Malic acid and oxalic acid spraying enhances phytic acid degradation and total antioxidant capacity of mung bean sprouts

In this study, effects of two organic acids spraying on the growth profiles, phytic acid content, antioxidant capacity, phytase activity and related genes expression during mung bean germination were investigated. Results showed that both oxalic acid and malic acid spraying were effective ways to improve the degradation of phytic acid by inducing phytase activity and the related genes expression, but no significant difference was found in phytic acid content between the two treatments. The contents of total phenolics and MDA (malondialdehyde) in oxalic acid spraying were higher, whereas ascorbic acid content and sprout length in malic acid spraying was higher. Both organic acid treatments could increase antioxidant capacities, but higher antioxidant capacities were found in oxalic acid spraying due to higher total phenolics content and antioxidant enzyme activity.     

Drying kinetics,physico‐chemical properties,antioxidant activity and phenolic composition of foam‐mat dried germinated rice bean (Vigna umbellata) hydrolysate

This research was aimed to study physico‐chemical properties and antioxidant activities of foam‐mat dried germinated rice bean (Vigna umbellata) hydrolysate. Germination led to an increase in released phenolic content and antioxidant activity (DPPH radical scavenging activity and FRAP) of rice bean hydrolysate. The hydrolysate obtained from germinated rice bean (GRB) and non‐germinated rice beans (NGRBs) was foam‐mat dried at 60 and 70 °C. Semi‐theoretical and empirical model could suitably describe the drying characteristic of foamed bean hydrolysate. Total phenolic content and antioxidant activities of foam‐mat dried samples decreased with increasing air‐drying temperature (P ≤ 0.05). Gallic acid, catechol and epicatechin were major phenolic compounds in foam‐mat dried samples prepared from both GRB and NGRB. The higher phenolic content and antioxidant activities were found in foam‐mat dried hydrolysate of GRB. Electron spin resonance spectrometry revealed that foam‐mat dried rice bean hydrolysate showed a strong ability to scavenge free radicals, especially carbon‐centred radicals.     

Amylose content,molecular structure,physicochemical properties and in vitro digestibility of starches from different mung bean (Vigna radiata L.) cultivars

Physicochemical and in vitro digestibility characteristics of starches isolated from six cultivars of mung bean (Vigna radiata L.) were studied. Significant differences (p < 0.05) were observed between the cultivars with respect to amylose content (29.9–33.6%), relative crystallinity (29.0 to 31.7%), particle diameter (16.2–17.1 µm) and molecular weight of amylopectin (260–289 × 10⁶ g/mol). The scanning electron micrographs revealed the presence of large oval to small round shape granules with average particle diameter of 16.2–17.1 µm. The X‐ray diffraction pattern was of the C‐type. The enthalpies of gelatinization and retrogradation were 8.9–10.3 and 4.6–6.3 J/g, respectively. The amounts of slowly digesting and resistant starch of mung bean followed the order: PBM‐1 > SML‐32 > ML‐613 > SML‐134 > ML‐267 > ML‐5 and ML‐5 > ML‐267 > SML‐134 > ML‐613 > SML‐32 > PBM‐1, respectively. The six starches exhibited significant (p < 0.05) differences in their pasting parameters. Correlation analysis showed that amylose content, granule diameter and relative crystallinity values were important in determining thermal, pasting and in vitro digestibility of starches.     

Green method for determination of phenolic compounds in mung bean (Vigna radiata L.) based on near‐infrared spectroscopy and chemometrics

Mung bean grains exhibit high level of antioxidant activity due the presence of phenolic compounds. Near‐infrared spectroscopy (NIRS), in conjunction with chemometrics, was used to develop a rapid, nondestructive, chemical free and easy‐to‐use method to determine these compounds in sixty genotypes of mung bean. NIRS calibration curve with high‐performance liquid chromatography (HPLC) as reference method was used to determine phenolic compounds (catechin, chlorogenic acid, caffeic acid, p‐coumaric acid, t‐ferulic acid, vitexin, isovitexin, myricetin, quercetin and kaempferol). It was observed that partial least square regression (PLSR) model in the wavelength range of 1600–2500 nm with standard normal variate (SNV) and linear baseline correction (LBC) as preprocessing techniques can measure phenolic compound accurately (R² > 0.987) with root‐mean‐square error less than 1.82%. This study shows that NIRS along with chemometrics is an accurate method to estimate the phenolic compounds rapidly and nondestructively.     

Effect of UV‐B treatment during the growth process on the postharvest quality of mung bean sprouts (Vigna radiata)

The production patterns and nutritious qualities of mung bean sprouts are in line with the consumption needs of modern people. This study was conducted to explore the effects of low doses of UV‐B irradiation on the 3‐day growth period of mung bean sprouts. The results showed that, when mung bean sprouts were irradiated with UV‐B (0.738 kJ m^?2) for 1 h per day, their total phenolic content increased by 22.80%, and the activity of polyphenol oxidase decreased by 45.45%. Hypocotyl epidermis stomata were closed, reducing water loss and the opportunity for microbes to invade plants, leading to the maintenance of freshness of the sprouts. In conclusion, UV‐B irradiation for 1 h per day during the growth of mung bean sprouts can effectively improve their preservation. This method is a low‐cost, environmental friendly and pollution‐free physical preservation technique, and it has good application prospects.     

Desiccant drying prior to hermetic storage extends viability and reduces bruchid (Callosobruchus chinensis L.) infestation of mung bean (Vigna radiata (L.) R. Wilczek) seeds

Seeds of mung bean (Vigna radiata (L.) R. Wilczek) are subject to loss of viability due to aging and damage from pulse beetles (or bruchids; Callosobruchus spp.) infestation during storage. We investigated whether seed drying using desiccants and hermetic packaging would prevent or ameliorate these consequences of storage. Sun-dried mung bean seeds at a moisture content of 10% were subjected to further drying for 72 h using five different desiccants: Drying Beads® (a zeolite-based desiccant), silica gel, sodium aluminum silicate, activated alumina, and cow-dung ash (a traditional desiccant). Seeds were subsequently stored in hermetic plastic containers in the presence of these desiccants under ambient conditions along with sun-dried seeds stored in cloth bags or in hermetic containers. In addition, parallel samples of each treatment were inoculated with one pair of bruchid beetles (C. chinensis L.) and stored under the same conditions. The seed drying treatments did not affect initial seed quality (germination percentage and seedling vigor) significantly. After storage for 9 months at ambient temperatures, seeds dried using Drying Beads, silica gel, sodium aluminum silicate and activated alumina had higher germination percentages, seedling vigor indices and soil emergence, and lower electrical conductivity (leakage upon imbibition) and fungal infestation compared to other conditions. In addition, the mung bean seeds inoculated with bruchids and stored with these effective desiccants had less damage, oviposition, and insect respiratory activity in the hermetic containers and maintained higher seed germination and seedling vigor after six months of storage compared to other treatments and controls. The results demonstrate the superior ability of desiccants to quickly and safely dry seeds prior to and during storage and the benefits of such drying and hermetic storage conditions for preventing seed deterioration and insect damage during storage.