Changes in phenolic content, phenylalanine ammonia-lyase (PAL) activity, and antioxidant capacity of two buckwheat sprouts in relation to germination

Bioactive components and functional properties of biologically activated cereal grains: A bibliographic review

Whole grains provide energy, nutrients, fibers, and bioactive compounds that may synergistically contribute to their protective effects. A wide range of these compounds is affected by germination. While some compounds, such as β-glucans are degraded, others, like antioxidants and total phenolics are increased by means of biological activation of grains. The water and oil absorption capacity as well as emulsion and foaming capacity of biologically activated grains are also improved. Application of biological activation of grains is of emerging interest, which may significantly enhance the nutritional, functional, and bioactive content of grains, as well as improve palatability of grain foods in a natural way. Therefore, biological activation of cereals can be a way to produce food grains enriched with health-promoting compounds and enhanced functional attributes.

Electrically induced changes in amaranth seed enzymatic activity and their effect on bioactive compounds content after germination

Electric treatment applied to seeds and sprouts can change their phytochemical composition. However, only a handful of studies have investigated the effects of treating seeds with electric current prior to their germination on the enzymatic antioxidant system of their sprouts. The aim of this study was to determine the changes in bioactive compounds and the enzymatic antioxidant activities in seeds and amaranth sprouts under direct electric current (DC) treatments. Amaranth seeds were treated with DC at 500 mA for different periods of time (0, 2, 5, 10 and 30 min) and let sprout (85% RH, 25 ± 2 °C) for 6 days. Significant changes were found in the antioxidant enzymatic activities and in the total content of flavonoids (15.44 ± 0.56 mg RE/gDW) and phenolic compounds (35.87 ± 0.17 mg GAE/gDW) in 6-day-old sprouts from DC-treated seeds in comparison to sprouts form non-treated seeds. The results suggested that DC treatment for short period (5 min) can induce quantitative changes to the enzymatic antioxidant system of amaranth sprouts, thus representing a relatively cost-effective method for enhancing health-improving properties of sprouts.

Changes of the phenolic compounds and antioxidant activities in germinated adlay seeds

BACKGROUND

Over the years, germinated adlay products have been used as both food source and folk medicine. This study investigated the changes of total phenolic content (TPC), total flavonoid content (TFC), antioxidant activities, and phenolic acid profiles of adlay seed during germination.

RESULTS

Results revealed that phenolic compounds and antioxidant activities varied with the germination stages. Germination significantly increased the free form phenolic and flavonoid contents by 112.5% and 168.3%, respectively. However, both of the bound form phenolic and flavonoid contents significantly decreased after germination. Phenolic acid compositions were quantified via HPLC analysis, and the levels of vanillic, p-coumaric, caffeic, hydroxybenzoic and protocatechuic acids in the free phenolic extracts were found to be significantly increased. The improvement of the free and total phenolic and flavonoid contents by the germination process led to a significant enhancement of the antioxidant activities (evaluated by the ABTS, FRAP and ORAC assays). The TPC showed the highest correlation with ORAC values (r = 0.9979).

CONCLUSION

Germinated adlay had higher free and total phenolic and flavonoid contents, and antioxidant activities than ungerminated adlay. This study indicates that germinated adlay could be a promising functional food, more suitable for human consumption. © 2017 Society of Chemical Industry.

Effect of Light- and Dark-Germination on the Phenolic Biosynthesis, Phytochemical Profiles, and Antioxidant Activities in Sweet Corn (Zea mays L.) Sprouts

Sweet corn is one of the most widely planted crops in China. Sprouting of grains is a new processes to increase the nutritional value of grain products. The present study explores the effects of light on the nutritional quality of sweet corn sprouts. Gene expression of phenolic biosynthesis, phytochemical profiles and antioxidant activity were studied. Two treatments (light and dark) were selected and the morphological structure of sweet corn sprouts, as well as their biochemical composition were investigated to determine the effects of light on the regulation of genes responsible for nutritional compounds. Transcription analyses for three key-encoding genes in the biosynthesis of the precursors of phenolic were studied. Results revealed a negative regulation in the expression of _ZmPAL with total phenolic content (TPC) in the light group. TPC and total flavonoid content (TFC) increased during germination and this was correlated with an increase in antioxidant activity (r = 0.95 and 1.0). The findings illustrate that the nutritional value of sweet corn for the consumer can be improved through germination to the euphylla stage.

Influence of Indole-3-Acetic Acid and Gibberellic Acid on Phenylpropanoid Accumulation in Common Buckwheat (Fagopyrum esculentum Moench) Sprouts

We investigated the effects of natural plant hormones, indole-3-acetic (IAA) acid and gibberellic acid (GA), on the growth parameters and production of flavonoids and other phenolic compounds in common buckwheat sprouts. A total of 17 phenolic compounds were identified using liquid chromatography-mass spectrometry (LC-MS) analysis. Among these, seven compounds (4-hydroxybenzoic acid, catechin, chlorogenic acid, caffeic acid, epicatechin, rutin, and quercetin) were quantified by high-performance liquid chromatography (HPLC) after treating the common buckwheat sprouts with different concentrations of the hormones IAA and GA. At a concentration of 0.5 mg/L, both IAA and GA exhibited the highest levels of growth parameters (shoot length, root length, and fresh weight). The HPLC analysis showed that the treatment of sprouts with IAA at concentrations ranging from 0.1 to 1.0 mg/L produced higher or comparable levels of the total phenolic compounds than the control sprout and enhanced the production of rutin. Similarly, the supplementation with 0.1 and 0.5 mg/L GA increased the content of rutin in buckwheat sprouts. Our results suggested that the treatment with optimal concentrations of IAA and GA enhanced the growth parameters and accumulation of flavonoids and other phenolic compounds in buckwheat sprouts.

Deficit irrigation strategies enhance health-promoting compounds through the intensification of specific enzymes in early peaches

BACKGROUND

Biochemical and enzymatic responses to long-term regulated deficit irrigation (RDI) at harvest, during cold storage and after the retail sale period of 'Flordastar' early peaches were evaluated. Irrigation strategies were Control, and two RDI applied during post-harvest period (RDI1 , severe; RDI2 , moderate), based on different thresholds of maximum daily shrinkage signal intensity (RDI1 , 1.4 to dry; RDI2 , 1.3 to 1.6).

RESULTS

Both RDI provoked stress in the plant. This meant higher antioxidant concentration [averaging 1.30 ± 0.27 g ascorbic acid equivalents (AAE) kg(-1) fresh weight (FW) for control and 1.77 ± 0.35 and 1.50 ± 0.30 g AAE kg(-1) FW for RDI1 and RDI2 , respectively]. Antioxidant levels decreased with storage by polyphenoloxydase action, which increased (from 0.04 ± 0.01 U mg(-1) protein to 0.32 ± 0.08 U mg(-1) protein). Vitamin C was initially higher in RDI samples (44.22 ± 0.05 g total vitamin C kg(-1) FW for control vs. 46.77 ± 0.02 and 46.27 ± 0.03 g total vitamin C kg(-1) FW for RDI1 and RDI2 , respectively).

CONCLUSION

The way RDI was applied affected bioactive fruit composition, being catalase and dehydroascorbic acid good water stress indicators. RDI strategies can be used as field practice, allowing water savings while enhanced healthy compound content in early peaches.

Chemical composition and health effects of Tartary buckwheat

Tartary buckwheat (Fagopyrum tataricum) contains a range of nutrients including bioactive carbohydrates and proteins, polyphenols, phytosterols, vitamins, carotenoids, and minerals. The unique composition of Tartary buckwheat contributes to their various health benefits such as anti-oxidative, anti-cancer, anti-hypertension, anti-diabetic, cholesterol-lowering, and cognition-improving. Compared with the more widely cultivated and utilised common buckwheat (F. esculentum), Tartary buckwheat tends to contain higher amounts of certain bioactive components such as rutin, therefore, showing higher efficiency in preventing/treating various disorders. This review summarises the current knowledge of the chemical composition of Tartary buckwheat, and their bio-functions as studied by both in vitro and in vivo models. Tartary buckwheat can be further developed as a sustainable crop for functional food production to improve human health.

Potentially bioaccessible phenolics, antioxidant activity and nutritional quality of young buckwheat sprouts affected by elicitation and elicitation supported by phenylpropanoid pathway precursor feeding

This paper presents the study on impact of elicitation and the phenylpropanoid pathway feeding on the nutritional quality, the potentially bioaccessible phenolics and the antioxidant capacity of young buckwheat sprouts. Phenolics content was increased by elicitation and feeding with tyrosine and shikimic acid--an elevation of 30% and 17%, respectively. Antioxidant capacity was improved by feeding with tyrosine--an increase of 16.7% and 17.1% in both untreated and treated sprouts, respectively. The highest protein digestibility was determined for the control sprouts and those obtained after tyrosine feeding. The lowest starch digestibility was found for elicited sprouts obtained from seeds fed with tyrosine (a decrease by 52%). An increase of expected glycemic index by 38% was determined for elicited sprouts obtained after phenylalanine feeding. Starch and protein digestibility were negatively correlated with total phenolics (r = -0.55 and -0.58, respectively), however starch digestibility was also affected by resistant starch content.

Elicitation and precursor feeding as tools for the improvement of the phenolic content and antioxidant activity of lentil sprouts

This study considered the efficacy of UV-B treatment and precursor feeding with phenolic synthesis precursors in relation to the production of polyphenol-rich sprouts. The used modifications of sprouting caused an increase in the activities of tyrosine ammonia-lyase and phenylalanine ammonia-lyase. The biotechnological approaches used allowed for a significant enhancement of the antioxidant potential of sprouts that was strongly and positively correlated with total phenolic content. The highest increase of flavonoids content was found for the sprouts obtained with phenylalanine treatment (2.41mg/gFM, 1.6-fold with respect to the control). The highest increase in the antioxidant capacity was found for the sprouts obtained with phenylalanine (an increase of 27% after solid-liquid extraction) and combined UV-tyrosine treatments (an increase of 44% for potentially bioaccessible fractions). The results of this work may suggest the use of elicitation supported by precursor feeding as an easy and cheap tool for improving the nutraceutical potential of low-processed food.