American Journal of Food Science and Technology

In this study, the relationships between the electrical conductivity and temperature for different milk fat contents were investigated during the incubation of kefir. For kefir production, three milk samples at different fat contents (0.15, 1.7 and 3.0%) and two incubation temperatures (25 °C and 35 °C) were selected. The inoculum level was 2%. The kefir fermentation time was approximately 10 h and the pH of kefir samples were 4.4 in the last stage. The test results showed that electrical conductivity (EC) increased at both the temperatures. The average EC values of non fat milk kefir were in the range of 4.72 mS/cm – 6.4 mS/cm at 35 °C, and 4.72 mS/cm – 5.71 mS/cm at 25 °C. The average EC values of full fat milk kefir were in the range of 4.84 mS/cm – 6.41 mS/cm at 35 °C, and 4.84 mS/cm – 5.63 at 25 °C. The average EC values of low fat milk kefir were in the range of 4.54 mS/cm – 6.39 mS/cm at 35 °C, and 4.54mS/cm – 5.5 mS/cm at 25 °C. Electrical conductivity of samples showed little improvement at low incubation temperature and fat content. Statistically, there was a significant difference (p < 0.05) in EC among samples.

American Journal of Food Science and Technology. 2016, 4(1), 25-28. DOI: 10.12691/ajfst-4-1-5
Pub. Date: February 02, 2016

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Effect of Frozen Storage on the Chemical Stability, Functional and Sensory Properties of ‘Ogbono’ (Irvingiagarbonensis var. excelsa) and ‘Egusi’ (Citrullus vulgaris schrad) Seed Flours

by Ohwesiri Monday Akusuand and David Barine Kiin-Kabari

Original Research

‘Ogbono’ (Irvingiagarbonensis var. excelsa) and ‘egusi’ (Citrullusvulgaries Schrad) seed flours were packaged separately in vacuum sealed high density polyethylene bags of 0.7mm thickness and were subjected to frozen storage by storing the packs in a domestic deep freezer for up to four months. Samples were removed at intervals of 0, 1, 2, 3 and 4 months for analysis. The effects of frozen storage on the shelf-stability factors (moisture, free-fatty acids and peroxide values), selected functional properties of water/oil absorption capacity, foam capacity and viscosity and sensory attributes of the frozen ‘ogbono’ and ‘egusi’ samples were investigated. The result of this investigation shows that there was no significant difference (p>0.05) in storage life (shelf stability factors), selected functional and sensory properties of both “ogbono” and ‘egusi’ seed flours frozen up to three months. However, all the shelf-stability properties, selected functional and sensory properties of both flour samples decreased significantly (p<0.05) after four months of frozen storage. Therefore, frozen storage at -18°C could be used to preserve the storage life, functional and sensory properties of vacuum packaged ‘ogbono’ and ‘egusi’ seed flours up to three months in moisture/gas-impermeable polyethylene packs of 0.7mm thickness without losing its sensory properties.

American Journal of Food Science and Technology. 2016, 4(1), 20-24. DOI: 10.12691/ajfst-4-1-4
Pub. Date: January 18, 2016

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Effect of Wrapping Materials on Physico-chemical and Microbiological Qualities of Fermented Melon Seed (Citrullus colocynthis L.) Used as Condiment

by Anne I. Peter-Ikechukwu, Ngozi O. Kabuo, Serah O. Alagbaoso, Njideka E. Njoku, Chioma N.Eluchie. and Williams O. Momoh

Original Research

The effect of six different wrapping materials on physico-chemical and microbiological qualities of fermented melon seed (Citrullus colocynthis L) was studied. Melon seeds were sorted, washed, boiled (48 hrs), dehulled and wrapped in blanched plantain leaf, then it was boiled again for 2 hours, drained, cooled and allowed to ferment naturally for 72 hours. The fermented melon seeds were then mashed, wrapped with six different wrapping materials include: fresh, blanched and dried of thaumatococcus danielli leaf, aluminum foil, black polyethylene and transparent polyethylene, placed in a warm environment for 72 hours (maturation period). The products which are known as Ogiri condiment were subjected to microbiological and physico-chemical evaluation. The results of the microbiological evaluation showed that the predominant bacteria involved were Bacillus spp, Enterococcus spp and Corynebacterium spp. While Saccharomyces cerevisae was isolated. The results of the physico-chemical evaluation showed increase in pH from 5.5 to 6.3, Titratable acidity (TTA) increased from 0.2% to 0.49% during fermentation and varied during maturation. Alumininum foil had the highest TTA of 0.43% while transparent polyethylene had the lowest TTA of 0.23%. During fermentation, the amino nitrogen increased from 2% to 5.5%. The amino nitrogen also increased appreciably during maturation. Black polyethylene had the highest amino nitrogen value (21.15%) while aluminum foil had the least value of amino nitrogen (15.65%) at 72 hours.

American Journal of Food Science and Technology. 2016, 4(1), 14-19. DOI: 10.12691/ajfst-4-1-3
Pub. Date: January 05, 2016

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Effect of Some Thermal Processing Techniques on the Anti- nutritional Factors of Canavalia plagiosperma Piper Seeds

by Serah O. Alagbaoso, Justina N. Nwosu, Ijeoma .M. Agunwa, Njideka E. Njoku, Linda O. Akajiaku and Chioma N. Eluchie

Original Research

The effect of some thermal processing techniques on the anti-nutritional factors of Canavalia plagiosperma Piper seeds was studied. Raw seeds of Canavalia plagiosperma Piper (Oblique- seeded Jack bean) were autoclaved (at 121°C, 15 psi for 25, 30 and 35 minutes), cooked (at 100°C for 30, 40 and 50 minutes) and roasted (at 120°C for 40, 60 and 80 minutes). The anti-nutritional factors of the processed and raw samples were determined. Six (6) anti-nutrients (alkaloid: 1.17%, haemagglutinin: 20.31 Hu/mg, hydrogen cyanide: 4.70 mg/kg, raffinose: 0.64%, stachyose: 1.09%, steroid: 0.38%) were determined in the raw seed. The three processing treatments given to the seed showed a general reduction trend on these six anti-nutrients at different rates and levels. From the results, autoclaving was the best processing method for haemagglutinin (0.05 Hu/mg), raffinose (0.06%), stachyose (0.22%) and steroid (0.02%) while cooking was the best processing treatment for alkaloid (0.04%) and hydrogen cyanide (0.83 mg/kg). Roasting had the least reduction effect on the six anti- nutrients investigated. The results, therefore, suggest that moist heat treatments (autoclaving and cooking) significantly lowered the levels of antinutrients in Canavalia plagiosperma Piper seeds, thereby making it safer for consumption.

American Journal of Food Science and Technology. 2016, 4(1), 7-13. DOI: 10.12691/ajfst-4-1-2
Pub. Date: January 04, 2016

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Efect of Phytol on Dehydrogenase Activity of Bacterial Isolates from Grilled Meat

by ELUCHIE C.N., ORANUSI S., AKUJOBI C. O. and ALAGBAOSO S.O.

Original Research

Effect of phytol on the dehydrogenase activity of Staphylococcus aureus Bacillus cereus, Pseudomonas aeruginosa and Enterococcus faecalis isolated from grilled meat was examined via dehydrogenase assay using 2,3,5 – tripheny tetrazolium chloride (TTC) as the electron acceptor. The bacteria isolates were exposed to various concentrations of phytol (0-2000 μg) in a nutrient broth. The minimum inhibitory concentration (MIC) and minium bactericidal concentration (MBC) values of phytol against the bacterial isolates were found in the range of 31.25 μg /ml to 250 μg /ml and 125 μg /ml to 250 μg /ml respectively. Effect of phytol on the dehydrogenase activity of the bacterial isolates showed that gram negative Pseudomonas aeruginosa had higher dehydrogenase activity than the gram positive Bacillus cereus, Enterococcus faecalis and Stpahylococcus aureus. The effect of phytol on the dehydrogenase activity varied significantly among the bacterial isolates. This result indicates that phytol could be used as an antibacterial agent in food industry to inhibit the growth of certain food borne pathogens.

American Journal of Food Science and Technology. 2016, 4(1), 1-6. DOI: 10.12691/ajfst-4-1-1
Pub. Date: January 04, 2016

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