Proximate, Mineral and Functional Properties of Maize Starch Complemented with Defatted Sesame Seed Flour

Background: Maize is known to be one of the major cereals used as indigenous breakfast meal and for infant weaning. It is high in carbohydrate with limited protein content and deficient in lysine. There is a need to complement its nutritional attributes with the inclusion of sesame seed flour known to be rich source of protein, fat and some essential minerals to maximize adequate nutrition and minimize mal nutrition that could result from the deficiency of these essential nutrients. Objectives: The physicochemical properties of maize starch complemented with defatted sesame seed flour were investigated.  Methods: Maize grains and sesame seed were processed into starch and flour respectively. The ratio of maize starch to sesame seed flour was 90:10, 85:15, with 100% maize starch as control and 100% maize flour as control. The samples were evaluated for proximate, mineral and functional properties using standard analytical procedure. Results: The proximate composition varies significantly (P≤0.05).The moisture content was in the range of (9.25 to 12.0%), protein (10.58 to 21.70%), crude fiber (0.50 to 3.0%), fat content(1.75 to 10.0%), ash content (1.35 to 3.45%) and carbohydrate (50.55 to 72.67%).The mineral composition shows no significant difference (P≤0.05). Copper was in the range of (0.29 to 0.33 mg/100g), potassium (2.08 to 2.13 mg/100g), sodium (3.67 to 3.72 mg/100g), magnesium (0.77 to 0.84 mg/100g) and manganese (1.47 to 1.54 mg/100g). Most of functional properties investigated show no significant difference (P≤0.05). Bulk density was in the range of (0.62 to 0.64g/ml), swelling power (4.75 to 8.56 g/ml), water absorption capacity (1.8 to 3.0 g/g), oil absorption capacity (1.35 to 1.70 g/g) and gelation capacity (8.20 to 11.90%). Conclusion: The inclusion of defatted sesame seed flour to maize starch during processing can significantly improve proximate, mineral and the functionality of the blends.    Keywords: Maize starch, physicochemical properties, sesame seed flour&nbsp

Comparative studies of the dough raising capacity of local yeast strains isolated from different sources

Background: Fermentation by yeast is of primary importance for its leavening function and its possible contribution to the production of desirable flavoured compounds. Objectives: This study focused on the isolation of local yeast strains from different sources: fresh pineapple juice, palm wine and orange juices and Burukutu. Methods:  Fresh pineapple juice, palm wine and orange juices and Burukutu were kept on a sterile workbench to be fermented at ambient temperature for 72 hours. Aliquots of the fermented samples were introduced into conical flasks containing yeast extract glucose peptone broth compounded for isolation and characterization. Yeast isolated from pineapple, burukutu, orange and palm wine were characterized. The morphological, cultural and biochemical characteristics of the yeasts were identified by using API20C AUX Kit (Bio Meriux), tested for markers characteristics such as sugars fermentation ability and starch hydrolysis. Biomass of each isolate tested was used to ferment flour dough to determine their fermentative abilities. Five out of the seven yeast isolates were compared with the commercial baker yeast (control) in terms of their dough raising capacity to confirm their baking potentials. Sensory evaluation of the baked fermented dough was carried out using these parameters: texture, aroma, taste and appearance. Results: The yeasts were identified to be Saccharomyces cerevisiae,  Saccharomyces exiguus, Saccharomyces kluyveri and Saccharomyces ludwigii. Catalase and Urease were found to be identical with the baker’s yeast (Control). The results revealed that Saccharomyces cerevisiae, Saccharomyces exiguus and Saccharomyces ludwigii yeast isolates produced loaves that have sensory properties significant (p≤0.05) when comparable with baker’s yeasts commonly used in many of the bakeries. Conclusion: The findings in this study showed that it is possible to isolate a pure culture of Saccharomyces species from fermented fruits and local beverages for use in baking instead of importing the commercial baker’s yeast that is expensive. These local isolates if used will economize our foreign reserve. Keywords: Local yeast, Baker’s yeast, Saccharomyces species, Dough raisin

Shelf Stability, Microbiological and Physicochemical Studies of ‘Zobo’ Drink Pasteurized and Treated with Preservative

Background: The combined effect of pasteurization, improved hygiene and varied concentrations of sodium benzoate on the shelf stability and physicochemical attributes of ‘Zobo’ drink, a nutritious non-alcoholic indigenous beverage was evaluated. Objectives: To evaluate the combined effects of pasteurization, improved hygiene and food preservatives on the shelf stability of ‘Zobo’ drink. Methods: Freshly prepared ‘Zobo’ samples were aseptically dispensed in 100 mL capacity Polyethylene terephthalate (PET) bottles containing various concentrations of sodium benzoate (0.05%, 0.25%, 0.50%, 0.75% and 1.00%). Six ‘Zobo’ samples were produced from the fresh ‘Zobo’ using a modified method that combined Hurdle Technology and Hazard Analysis and Critical Control Points (HACCP) for preservation and stored for eight weeks on the shelf. Analyses were carried out weekly on loss in vitamin C content, microbial quality and physicochemical properties of the beverage for eight weeks. Results: Parameters analysed significantly (p<0.05) changed considering the methods of treatment and storage period. Pasteurization at 68oC for 20 minutes eliminated successfully all pathogenic organisms and coliforms as none was isolated from the drink throughout the eight weeks of shelf study. Saccharomyces cerevisiae and Lactobacillus fermentum isolated from the samples during storage were responsible for the deterioration and spoilage of the beverage. Conclusion: Although the five different concentrations of the preservative used in combination with pasteurization were effective in extending the shelf life of the beverage, sample Bz 0.05% preserved better than all others without impacting negatively on the vitamin C content and other physicochemical properties of the drink. Keywords: Zobo, Hibiscus sabdariffa, Sodium Benzoate, Pasteurization, shelf lif

Determination of Mineral and Toxic Elements in Rice (Oryza Sativa L.) Produced in Three Locations of Niger State, North-Central, Nigeria

Background: Accumulation of heavy metals in the human body may result in toxic effects. They are universally found in the earth's crust and tend to accumulate in crops grown in heavily contaminated soil and hence enter the food chain. On the other hand, some mineral elements are required in a small amount (micronutrients) or large quantity (macronutrients) for the proper functioning of both plant and animal body systems. Objectives: This study determined the toxic and mineral elements in rice (Oryza sativa) varieties produced in three locations of Niger State, North-Central, Nigeria.  Methods: Toxic and mineral elements analysis was conducted on rice samples obtained from three locations in Niger State. Calcium (Ca), Magnesium (Mg),  Phosphorus (P), Copper (Cu), Manganese (Mn), Zinc (Zn), Nickel (Ni), Cadmium (Cd), Chromium (Cr) and Lead (Pb) were analyzed using Atomic Absorption Spectroscopy, while Sodium (Na) and Potassium (K) were determined using a photoelectric flame photometer. Results: Sodium concentrations ranged from 1.33 mg/kg to 1.41 mg/kg; potassium, 3.22 mg/kg to 3.97 mg/kg; calcium, 0.67 mg/kg to 0.88 mg/kg; magnesium, 7.20 mg/kg to 8.25 mg/kg;  phosphorus, 5.82 mg/kg to 7.22 mg/kg; copper, 0.40 mg/kg to 1.35 mg/kg; manganese, 0.15mg/kg to 0.25 mg/kg; zinc, 1.60 mg/kg to 2.90 mg/kg; and nickel, 2.21 mg/kg to 2.24 mg/kg. Lead, cadmium and chromium were not detected in the rice samples. Conclusions: While the toxic metals (Pb, Cd and Cr) were not detected, the concentrations of heavy metals (Cu, Mn, Zn and Ni) were lower than the FAO and WHO recommended level. It can therefore be concluded from this study that rice produced from these locations at the time of study is safe and may not pose immediate health hazards to consumers.   Keywords: Rice, toxic elements, mineral element