Antioxidant potential and α-glucosidase inhibitory activity of onion (Allium cepa L.) Peel and bulb extracts

Allium cepa L. is a commonly consumed vegetable that belongs to the Amaryllidaceae family and contains nutrients and antioxidants in ample amounts. In spite of the valuable food applications of onion bulb, its peel and outer fleshy layers are generally regarded as waste and exploration of their nutritional and therapeutic potential is still in progress with a very slow progression rate. The present study was designed with the purpose of doing a comparative analysis of the antioxidant potential of two parts of Allium cepa, i.g., bulb (edible part) and outer fleshy layers and dry peels (inedible part). Moreover, the inhibitory effect of the onion bulb and peel extracts on rat intestinal α-glucosidase and pancreatic α-amylase of porcine was also evaluated. The antioxidant potential of onion peel and bulb extracts were evaluated using 2,2-diphenyl- 1-picryl hydrazyl (DPPH), ferric-reducing antioxidant power assay (FRAP), 2,2’-azino-bis- 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assay, H2O2 radical scavenging activity and Fe2+ chelating activity. Total flavonoids and phenolic content of ethanolic extract of onion peel were significantly greater as compared to that of onion bulb. Ethanolic extract of onion peel also presented better antioxidant and free-radical scavenging activity as compared to the ethanolic extract of bulb, while the aqueous extract of bulb presented weakest antioxidative potential. Onion peel extract’s α-glucosidase inhibition potential was also correlated with their phenolic and flavonoid contents. The current findings presented onion peel as a possible source of antioxidative agents and phenolic compounds that might be beneficial against development of various common chronic diseases that might have an association with oxidative stress. Besides, outer dry layers and fleshy peels of onion exhibited higher phenolic content and antioxidant activities, compared to the inner bulb. The information obtained by the present study can be useful in promoting the use of vegetable parts other than the edible mesocarp for several future food applications, rather than these being wasted.Peer reviewe

KOMBINASI PUPUK ORGANIK CAIR (POC) KULIT BAWANG PADA BERBAGAI MEDIA TANAM TERHADAP PERTUMBUHAN DAN HASIL MENTIMUN BABY (Cucumis sativus L. Var. Vanesa)

This study aims to determine the application of liquid organic fertilizer (POC) to various growing media on the growth and yield of baby cucumbers. The study used a factorile randomized block design (RAK) with control, the first factor consisted of 2 levels, namely P1, = POC of onion skin and P22 = POC of garlic skin while the second factor consisted of 3 levels M1 = Soil + Husk (: 1 ), M2 = Soil + Mushroom Blog Waste (2 : 1 ), M3 = Soil + cow manure (2 : 1 ) so that 6 combinations and 1 control were obtained so that there were 7 treatments which were repeated 3 times. The results showed that garlic peel POC gave a better response than POC on cucumber growth and yield variables. The combination of POC treatment of garlic peel and cow dung gave a value of 35.54 cm at the length of the plant at 21 DAP, the number of fruit per plant was 17.50 units, fruit weight per plant and fruit weight per hectare were 303.33 g and 30,69 ton/ha.Keywords: POC onion skin, planting medium, baby cucumber, mushroom baglog wast

Influences of Storage Conditions, Cultivation and Culinary Practices, On the Antioxidant Capacity of Red Bulbs of Some Onion Varieties Grown in Burkina Faso

Red onion bulb is a vegetable containing micronutrients with antioxidant properties. However, certain factors can have an impact on the content of these compounds. The present research evaluate the effects of parameters such as cultural practices, storage conditions and culinary practices, on the antioxidants content of red onion bulb of some varieties grown in Burkina Faso. The identification of the factors was carried out through field surveys, and their effects on the antioxidants content were assessed and appreciated through especially specific related bibliographic and laboratory test data. The results showed that84.78% of farmers use chemical fertilizers and all of them use chemical pesticides on onion crop. They don’t use premises or equipment suitable for storage. About dishes,7.61% of cooks, peel, cut and wash onion bulb before steam cooking, boiling water cooking or oil frying them at high temperature during 30 minutes to 3 hours. Some cooks use to braise onion bulb scales as ingredients for different dishes such as barbecue. Only 02,72% of cooks grind the onion bulbs with a pestle, before using the crushed as such on barbecue, or slow cooking it in different sauces. Research results show that these culinary practices contribute declining significantly the final intake of antioxidant for the consumer's body