No abstract

1Three varieties of Hibiscus sabdariffa were analyzed for their phytochemical content and 2 inhibitory potential on carbohydrate-digesting enzymes as a basis for selecting a variety for 3 wine production. The dark red variety was chosen as it was highest in phenolic content and 4 partially inhibited -glucosidase (maltase), with delphinidin 3-O-sambubioside, cyanidin 3-5 O-sambubioside and 3-O-caffeoylquinic acid accounting for 65 % of this activity. None of 6 the varieties significantly inhibited -amylase. Regarding Hibiscus sabdarifa wine, the effect 7 of fermentation temperature (20 and 30 ˚C) on the physicochemical, phytochemical and 8 aroma composition was monitored over 40 days. The main change in phytochemical 9 composition observed was the hydrolysis of 3-O-caffeolquinic acid and the concomitant 10 increase of caffeic acid irrespective of fermentation temperature. Wine fermented at 20 ˚C 11 was slightly more active for -glucosidase inhibition with more fruity aromas (ethyl 12 octanoate), but there were more flowery notes (2-phenylethanol) at 30 ˚C. 13

Seasonal variations in crops can alter the profile and amount of constituent compounds and consequentially any biological activity. Differences in phytochemical profile, total phenolic content and inhibitory activity on α-glucosidase (maltase) of Hibiscus sabdariffa calyces grown in South Western Nigeria were determined over wet and dry seasons. The phenolic profile, organic acids and sugars were analysed using HPLC, while inhibition of rat intestinal maltase was measured enzymically. There was a significant increase (1.4-fold; p ≤ 0.05) in total anthocyanin content in the dry compared to wet planting seasons, and maltase inhibition from the dry season was slightly more potent (1.15-fold, p ≤ 0.05). Fructose (1.8-fold), glucose (1.8-fold) and malic acid (3.7-fold) were significantly higher (p ≤ 0.05) but citric acid was lower (62-fold, p ≤ 0.008) in the dry season. Environmental conditions provoke metabolic responses in Hibiscus sabdariffa affecting constituent phytochemicals and nutritional value.

The proximate analysis and amino acid profile of the larva of Oryctes Monoceros were investigated. The mineral profile and antinutritional factors were also determined. A high protein content (36.45% dry weight) was recorded with the larva containing the essential amino acids in varying proportions in the amino acid profile. An ash content of (4.00% dry weight) was recorded containing high proportions of sodium, magnesium, iron and potassium.(440.0mg/100g, 175.0mg/100g, 85.00mg/100g, 38.40mg/100g, respectively). The other mineral elements, zinc, manganese and copper were also present in smaller quantities. The result of the antinutritional factors showed that levels of phytic acid (178mg/100g), tannin (14.3mg/100g) oxalate (2.1mg/100g) all fell within acceptable levels. In addition, the larva protein had a digestibility of 58.05%. The insect larva could serve as an alternative source of protein and other nutrients supplement in human and animal diet.