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Asare has being involved in a few publications,others are yet to be published or simply confidential

Effects of fermentation and cowpea fortification on the quality characteristics of maize-based nixtamalized foods

S. K. SEFA-DEDEH¹, S. Asare, E. O. Sakyi-Dawson, and E. O. Afoakwa. (1) Department of Nutrition and Food Science, University of Ghana, P.O.Box LG134, Legon, Accra, Ghana

Spontaneous lactic acid fermentation and cowpea fortification have been used as effective technologies for improving the nutritional qualities of cereal-based foods.

The objective of this study was to investigate the effect of fermentation and cowpea addition on the chemical, functional and sensory qualities of the formulated maize-based nixtamalized products.

A 3 x 2 x 2 factorial experiment with fermentation time (0, 24, 48 hours), cowpea (0 and 15%) and alkaline treatment (nixtamalized and non-nixtamalized corn) was used. The blends were dried using a cabinet drier, milled into flour and spices added and processed into a snack food. Samples were analysed for moisture, fat acidity, water absorption and swelling capacity. The cylinder probe test cell was used in a TA-XT2 Texture Analyzer to measure the hardness of processed snack foods. Sensory analysis was conducted to determine the overall acceptability of the snack products.

Fermentation and cowpea levels showed no significant effect (p<0.05) on the moisture contents of the products. Cowpea addition caused decreases in the water absorption capacities from 192.23 to 117.15 % in the unfermented nixtamalized sample whereas general increases were observed in the non-nixtamalized products. Similar observations were made for the swelling capacities of the products. No significant variations were observed in the fat acidity levels of the nixtamalized products with fermentation time and cowpea fortification. The texture (hardness) of the formulated products was acceptable. Sensory evaluation indicated that the presence of cowpea and fermentation in the products did not influence their acceptability by the panel.

Nixtamalized corn can be subjected to spontaneous fermentation with cowpea addition to produce products of acceptable chemical, functional and sensory qualities to help improve their nutritional quality as well as introduce variety into foods prepared from maize (Paper presented at the annual meeting of the Institute of Food Technologists,Anaheim,California,U.S.A, June 15-19,2002)

Topic- 1-octen-3-ol; Antimicrobial activity and potential application as a preservative in foods.

By : Samuel Asare, Department of Agrotechnology and Food Sciences, Wageningen University, The Netherlands.

The antimicrobial activity of 1-octen-3-ol was examined against selected food borne pathogens; two gram-positive bacteria (Listeria monocytogenes and Staphylococcus aureus), two gram-negative bacteria (Escherichia coli and Pseudomonas GK5-K19), yeast (Saccharomyces cerevisiae), fungal spores (Aspergillus niger and Penicillium paneum) and bacterial spores (Bacillus subtlis spores).

The survival of these strains in the presence of the compound at different temperatures (room temperature and 4^oC) and different time intervals (0 to 72 hours) was tested in saline solution, brain heart infusion broth, sterile juice and sterile milk. The effect of fat on the activity of the compound was studied by conducting challenge tests in the absence and presence of fat (vegetable oil) in a solution of the compound. With phosphate buffers of varying pH the effect of pH on the activity of the compound was investigated. The effect of the compound on the different microflora of vegetables and minced meat (tartaar) was also studied.

The compound exhibited a broad spectrum of action against all the pathogens tested with the effect on bacterial and fungal spores being lower than the other strains. On the average the activity of the compound in sterile milk and in some cases brain heart infusion broth were lower than the in the other media. The effective concentrations for most strains ranged from 0.1 to 1.0% and the effect began mostly after 2 hours. For Gram-positive, Gram-negative bacteria and yeast there was a biocidal effect, whereas for bacterial and in most cases of mould spores there was a biostatic effect. The compound worked better against the microflora of vegetables than minced meat (tartaar). The presence of fat significantly reduced the activity of the compound, while pH had no effect on the activity.

The compound could be an effective preservative of foods without fat.

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