Estimated daily per capita intakes of phenolics and antioxidants from coffee in the Korean diet

Comparative changes of health-promoting phytochemicals and sugar metabolism of two hardy kiwifruit (Actinidia arguta) cultivars during fruit development and maturity

INTRODUCTION

Hardy kiwifruit (Actinidia arguta) has an extensive range of nutritional and bioactive compounds and has been valued as a great resource for kiwifruit breeding. A better understanding of the dynamic changes of the composition and accumulation of nutritional compounds during fruit development and ripening is required before genetic or cultural improvements can be targeted.

METHODS

In the present study, the phytochemical analysis of two A. arguta cultivars 'Yilv' and 'Lvmi-1' showed that they comprised different morphology, with a higher fruit diameter while a lower vertical fruit diameter of 'Lvmi-1' compared with 'Yilv'. The antioxidant capacity of both cultivars decreased during the maturity time and showed no significant difference between them. Furthermore, although glucose gradually increased during the maturity time, the predominant sugar composition was speculated to be fructose in 'Lvmi-1' fruit while sucrose in 'Yilv' fruit at the early fruit developmental stages. Moreover, the predominant acids in 'Yilv' and 'Lvmi-1' were citric acid followed by quinic acid, malic acid, and oxalic acid. The expression of sugar- and starch-related genes encoding the crucial enzymes suggested different changes in 'Yilv' and 'Lvmi-1'. Notably, a subsequent correlation analysis showed a significant positive correlation between sucrose phosphate synthase (SPS) expression and glucose in 'Yilv', fructokinase (FK) expression, and starch content in 'Lvmi-1', implying their vital roles in sugar and starch accumulation. By contrast, a significant negative correlation between FK expression and fructose in 'Lvmi-1' fruit was observed.

RESULTS AND DISCUSSION

In summary, our results provide supplementary information for the dynamic changes of nutritional compounds and antioxidant capacity during hardy kiwifruit maturity time and give a clue for exploring the mechanism of sugar and starch accumulation in hardy kiwifruit.

Effect of Microwave Treatment on Adzuki Beans (Vigna angularis L.) under Dry State—Analyzing Microstructure, Water Absorption, and Antioxidant Properties

In this study, a microwave was used on adzuki beans (Arari and Geomguseul) without water, in order to investigate their changes in microstructure, water absorption, and antioxidative properties. As the microwave treatment time increased (2450 MHz, 0 to 60 s), the lightness, redness, and yellowness were reduced, and moisture content significantly decreased in both varieties. The microstructure space between the seed coat, cotyledon, and pores within the cotyledon were observed, due to the loss of moisture. Regardless of microwave treatment, the water absorption behavior of the adzuki beans was sigmoidal. However, the water absorption kinetics of Arari increased after microwave treatment, whereas with microwave-treated Geomguseul, the water absorption rate decreased, compared to the control, except for the sample treated for 30 s. During soaking, the water absorption and softening rates in the microwave-treated adzuki bean were twice as fast as the untreated beans. Antioxidant activity, total phenolic compounds, and total flavonoid compounds were greatly improved by microwave treatment. These results indicate that microwave treatment affects the color, hydration, and bioactive compounds, and it can be used as a pretreatment method before processing adzuki beans.

Influence of production systems on phenolic characteristics and antioxidant capacity of highbush blueberry cultivars

Blueberry is a crop grown worldwide due to the excellent quality and high polyphenol content of its fruit and tolerance to cold conditions. We investigated the influence of three production systems, namely an open field, heated greenhouse, and non-heated (plastic) greenhouse, on the phenolic characteristics (total phenolic, flavonoid, and anthocyanin content) and antioxidant capacities of "Spartan" (northern highbush), "Sharpblue" (southern highbush), and "O'Neal" (southern highbush) blueberry cultivars. The non-heated production system showed the highest phenolic characteristics and antioxidant capacity in "Spartan" and "O'Neal," while the open field production system showed the highest phenolic characteristics and antioxidant capacity in "Sharpblue." Derivatives of delphinidin and malvidin were two of the most abundant anthocyanins. The heated greenhouse production system resulted in larger amounts of delphinidin derivatives compared with the other production systems, while the blueberry grown in the non-heated greenhouse produced larger amount of malvidin derivatives. The anthocyanin profiles varied according to production system and blueberry cultivars. The principal component analysis loading plot of blueberries for individual anthocyanins explained over 95% of the total variance. In summary, the results of this study suggest that a strategic approach to blueberry production could elevate the phenolic content and antioxidant capacity of cultivated blueberry. PRACTICAL APPLICATION: The highbush blueberry, a rich source of bioactive polyphenols, is a popular fruit. The microclimate of the production system of highbush blueberries affects the concentrations of antioxidative phenolic compounds such as anthocyanins. Therefore, discovering and applying the appropriate method of production for each blueberry cultivar could facilitate production of high-quality blueberries rich in phenolic antioxidants.

Effect of various roasting, extraction and drinking conditions on furan and 5-hydroxymethylfurfural levels in coffee

Furan and 5-hydroxymethylfurfural (5-HMF) were quantified in 108 coffee models prepared considering the species/origin of the coffee beans, roasting temperature/time, mesh size used to sieve the ground coffee beans, type of extraction water and extraction method. The effect of drinking conditions, such as adding sugar or cream, on furan and 5-HMF levels, was also studied. The range of furan and 5-HMF in coffee samples were 5-362 ppb and 51-1143 ppm, respectively. Furan levels were increased by 198-560% with increasing roasting temperature/time and by 106-399% in cold-brew extracts compared with espresso extracts. Among the mesh sizes used, 500 μm with espresso extraction, and 710 μm with cold-brew extraction led to maximal furan levels. 5-HMF concentration was highest in Robusta coffee and espresso extracts, and decreased by 17-76% with increasing roasting temperature/time. In a drinking condition study, furan level was remained unchanged, even when sugar or cream were added.

Changes in phenolics, soluble solids, vitamin C, and antioxidant capacity of various cultivars of hardy kiwifruits during cold storage

Hardy kiwifruits (Actinidia arguta) contain various bioactive compounds such as vitamin C and phenolics and can withstand cold temperatures. Changes in soluble solid, vitamin C, total phenolic, and total flavonoid content, and antioxidant capacity of three cultivars of hardy kiwifruits (A. arguta × A. deliciosa cv. Mansu, A. arguta cv. Haeyeon, and A. arguta cv. Chiak) were comparatively evaluated for 8 weeks of storage at 1 ± 0.5 °C. After the 8 weeks of storage, soluble solid content of three cultivars increased, whereas their vitamin C content decreased. Throughout this storage period, total phenolic and flavonoid content of cv. Mansu and cv. Haeyeon remained the same, while antioxidant capacity of these two cultivars also remained similar but with slightly more variations. Cv. Chiak, however, showed a decrease in total phenolic and flavonoid content and antioxidant capacity. These results suggest that cold storage of the hardy kiwifruits maintains levels of bioactive compounds.

Organic Selenium as Antioxidant Additive in Mitigating Acrylamide in Coffee Beans Roasted via Conventional and Superheated Steam

Selenium is an essential micronutrient with significant antioxidant activity promising in mitigating the formation of acrylamide during high-temperature roasting. In this study, green coffee beans pretreated with selenium (Se-coffee) were investigated on their selenium uptake, selenium retention in green and roasted beans, antioxidant activities, and formation of acrylamide during conventional and superheated steam roasting. Comparisons were made with positive (pretreated without selenium) and negative (untreated) controls. The acrylamide formation was significantly inhibited in Se-coffee (108.9-165.3 μg/kg) compared to the positive and negative controls by 73.9% and 52.8%, respectively. The reduction of acrylamide by superheated steam roasting only observed in the untreated coffee beans (negative control) by 32.4% parallel to the increase in its antioxidant activity. Selenium pretreatment significantly increased antioxidant activity of the roasted Se-coffee beans after roasting although soaking pretreatment significantly reduced antioxidant activity in the green beans. Acrylamide reduction in the roasted coffee beans strongly correlated with the change in antioxidant capacities after roasting (∆FRAP, 0.858; ∆DPPH, 0.836). The results indicate that the antioxidant properties of the organic selenium suppressed acrylamide formation during coffee roasting.

Characterization of Ginkgo biloba Leaf Flavonoids as Neuroexocytosis Regulators

Ginkgo biloba leaf (GBL) is known as a potential source of bioactive flavonoids, such as quercetin, arresting the neuronal soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-zippering. Here, the GBL flavonoids were isolated in two different manners and then examined for their bioactivity, physicochemical stability, and biocompatibility. The majority of flavonoids in the non-hydrolyzed and acidolyzed isolates, termed non-hydrolyzed isolate (NI) and acidolyzed isolate (AI) hereafter, were rich in flavonol glycosides and aglycones, respectively. Glycosidic/aglyconic quercetin and kaempferol were abundant in both NI and AI, whereas a little of apigenin, luteolin, and isorhamnetin were found in AI. NI was more thermostable in all pH ranges than quercetin, kaempferol, and AI. NI and AI both inhibited neurotransmitter release from differentiated neuronal PC-12 cells. NI and AI showed 1/2–1/3 lower EC₅₀/CC₅₀ values than quercetin and kaempferol. The NI and AI exhibited no toxicity assessed by the tests on chorioallantoic membranes of hen’s eggs, removing toxicological concerns of irritation potential. Moreover, GBL isolates, particularly AI, showed antioxidant and anti-inflammatory activities in the use below the CC₅₀ levels. Taken together, these results suggest that GBL isolates that are rich in antioxidant flavonoids are effective anti-neuroexocytotic agents with high stability and low toxicity.