Effect of soaking and air-resting on the phytochemical, antioxidant, and antimicrobial properties of Piper guineense (Schum and Thonn) seeds.

BACKGROUND: Soaking and air-resting are processing steps in malting. This has been reported to increase metabolic and enzyme activities in rice paddy as a result of exposure of the grain to atmospheric oxygen. The present study evaluated the effect of soaking and air-resting on the phytochemical composition of Piper guineense seeds. The seed extracts were prepared by: soaking the seeds in water for 4 h; air-resting for 30, 60, 90, and 120 min; and re-soaking for another 4 h. The out-of-steep seeds were milled and an extract was formed by tissue homogenization and maceration using ethanol. The phytochemical, antioxidant, and antibacterial properties of the seed extract were determined using standard methods. RESULTS: The alkaloid, flavonoid, saponin, tannin, and total phenol contents were 0.126-0.268, 0.091-0.172, 0.080-0.123, 0.00-0.107, and 0.447-0.908 g kg-1 respectively. The antioxidant properties (reducing power) of the seed extracts were concentration-dependent and were in the range 1.08-3.24 g kg-1 at 8 mg mL-1 , 1.14-3.47 g kg-1 at 16 mg mL-1 , 1.30-3.35 g kg-1 at 24 mg mL-1 , 1.26-3.11 g kg-1 at 32 mg mL-1 , and 1.13-3.04 g kg-1 at 40 mg mL-1 , respectively. The antibacterial activities against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa showed that, at 100 mg mL-1 , the inhibition zone diameters of the seed extracts were in the range 10-23 mm. CONCLUSION: Soaking and air-resting of P. guineense seeds increased the phytochemical components of the seeds. The extracts from the seeds air-rested for 30 min showed the highest phytochemical contents and had the highest antioxidant and antimicrobial properties. © 2022 Society of Chemical Industry.

Hardness as a modification index for malting red and white sorghum (kaffir) grains.

BACKGROUND: This study investigated changes in the resistance to fracture of malting red and white sorghum grains using a hardness tester as another method for monitoring grain modification. RESULTS: Grain hardness decreased progressively from 134.35 N and 137.29 N in malting red and white sorghums and levelled off after 120 h at 76.98 N and 69.14 N. In the red grain malts traditionally used for burukutu production, moisture content (r = -0.983), dhurrinase activity (r = -0.981), malting loss (r = -0.981), free amino nitrogen (r = -0.909) and cold water extract (r = -0.908) were better indicators of grain hardness than root length (r = -0.89). In the white sorghum malts, malting loss (r = -0.988), dhurrinase activity (r = -0.954) and diastatic activity (r = -0.936) were better indicators of grain modification than root length (r = -0.916). The soluble nitrogen ratio at the end of malting was lower in the red (0.049) compared with the white (0.0548). CONCLUSION: Grain hardness using a hand-held tester is a simple, fast and good index of modification of malting red and white sorghum grains. Oven-dried red and white sorghum malts could be considered to be well modified at hardness values/indices below 77 N/0.5730 and 72 N/0.5036, respectively.

Production of maize-bambara groundnut complementary foods fortified pre-fermentation with processed foods rich in calcium, iron, zinc and provitamin A.

BACKGROUND: Maize-bambara groundnut complementary foods are deficient in calcium, iron, zinc and vitamin A. Food-to-food fortification could be cheaper, safer and more easily adopted by local communities compared to the use of chemically pure compounds and vitamins to enrich such foods. RESULTS: Maize-bambara groundnut complementary foods fortified for iron, zinc, calcium and vitamin A by blending with a multi-mix (1.41:1:2.25, w/w) of processed roselle calyces, cattle bones, and red palm oil in a 1:2.1 (w/w) ratio showed significant increases in calcium, iron, zinc and vitamin A contents of 3.26-4.225, 0.083-0.134 and 0.015-0.017 g kg(-1) and 4855.3-7493.7 microgRE kg(-1), respectively. CONCLUSION: The maize-bambara groundnut foods had calcium, iron, zinc and vitamin A contents that satisfy the proposed nutrient requirements for infants. Only the maize-bambara groundnut and maize-bambara groundnut malt fermented by backslopping [(MB)(b) and (MB(m))(b)] containing red palm oil emulsified with Brachystegia eurycoma had calcium contents significantly (P < 0.05) higher than Nutrend, a complementary food produced by Nestle (Nigeria) PLC. These products are from raw materials produced in commercial quantities by rural farmers using household level technologies which the rural and urban poor can more easily access in order to reduce micronutrient malnutrition.

Effect of amylase-rich flour (ARF) treatment on the viscosity of fermented complementary foods.

Grains of cowpea and maize and slices of fresh cassava, cocoyam, plantain, and yam were steep-fermented in water, while flours from the same plant materials were fermented by backslopping for 24 to 30 hours. The pH and apparent viscosity of the gruels from the resulting flours were determined. Loss in weight due to fermentation was higher in fresh tubers than in dry grains. The pH of the flours decreased during fermentation. Measurements showed that the apparent viscosity only of gruels from flours produced by backslopping decreased after 24 hours. The apparent viscosity of gruels from steep-fermented flours was higher than that of the unfermented flours and those produced by backslopping. The apparent viscosity reduction of gruels from steep-fermented flours using amylase-rich flour (ARF) from five-day white sorghum malt was better with the prepared gruels than when applied to the flour-in-tap-water suspension before it was used to prepare gruels. Viscosity reduction using ARF was also better with the fermented gruels than with gruels from unfermented flours. The implications of these results for the formulation of complementary flour blends for infant feeding are discussed.