by Abeer M. Abd Elhamid and Mervet M. Elbayoumi
Original Research
In this study, the possibility to release bioactive peptides from camel milk using heat treatments and fermentation of camel milk was investigated. Camel milk was heated at 80°C for 30, 60, 90 and 120min. Samples of yoghurts after their fermentation and during storage were determined for proximate physicochemical and bioactive activities. Results showed that heat treatments and fermentation process, decreased significantly the pH (P<0.01) and increased the total solids and protein (P<0.01) of yoghurt during storage. The ash content was almost unchanged, when the time of heat treatments of camel milk increased. Also, fermentation increased the antioxidant activities in yoghurt. SDS–PAGE electrophoretic patterns of camel milk showed that after heating camel milk at 80°C for 60min; α-S2caseins (α-S2-CN) was not detected, while after fermentation α-lactalbumin (α-la) and β-lactoglobulin (β-lg) were not significantly detected. The peptide fractions from yoghurt showed good potential to inhibit growth of Bacillus cereus (ATCC 9639), Escherichia coli (ACCT 8739) and Staphylococcus aureus (ATCC 6538). For all the above, the non-standard heat treatment of camel’s milk and fermentation are necessary for a future application in dairy industry to produce a bioactive peptides.
American Journal of Food Science and Technology. 2017, 5(3), 109-116. DOI: 10.12691/ajfst-5-3-6
Pub. Date: June 27, 2017
14653 Views3795 Downloads2 Likes
by Patience C. Obinna-Echem
Original Research
Akamu is a lactic acid bacteria fermented cereal-based food that complements infant diets in most African countries. The effect of fermentation with Lactobacillus (L.) plantarum starter culture and gamma-irradiation on the pasting and morphological properties of Akamu was investigated. The sensory property of porridges from the L. plantarum fermentation and artificially acidified maize slurries was also investigated. The irradiated ground maize (IGM) and its L. plantarum strain fermented samples had significantly (p<0.05) the lowest peak (128.70 – 135.33 RVU) and final viscosities (68.50 -108.33 RVU). Un-irradiated ground maize (GM) and the traditionally fermented samples had significantly (p<0.05) the highest pasting properties (1920.50 – 2641.00 and 3378.80 – 3819.00 RVU for peak and final viscosities respectively). Scanning electron microscopy revealed the granular structure of starch: fermented samples had etches, while irradiated granules were rough and different from its un-irradiated counterpart. Porridges of the un-irradiated ground maize and the traditionally fermented sample had thick and solid linkages against the weak and viscous nature of irradiated samples. The sensory attributes (flavour, sourness, and overall acceptability) of the porridges from L. plantarum fermented sample was significantly (p>0.05) the most acceptable to the assessors. This study revealed that irradiation lowered the pasting properties of the maize slurries and caused changes in the morphological properties of both the uncooked slurries and their porridges. The sensory attributes of Porridge from the L. plantarum fermented maize slurry were most acceptable to the assessors.
American Journal of Food Science and Technology. 2017, 5(3), 101-108. DOI: 10.12691/ajfst-5-3-5
Pub. Date: June 27, 2017
14217 Views3947 Downloads
by Booker Osodo, Daudi Nyaanga and Joseph Muguthu
Original Research
Various researchers have fitted experimental drying curves for various products to existing drying models. In this study, an experimental forced convection solar grain dryer was used to select the best fitting drying model for shelled maize. 0.04 m thick grain layer of shelled maize was dried an air velocity of 0.408 m/s and a 40°C drying air temperature. Using Root Mean Square Error (RMSE), Coefficient of Determination (R2) and Chi Square (χ2) the selected drying model was the one by Midilli et al. (2002), with R2, χ2 and RMSE values of 0.9487, 0.4278 and 0.1723 respectively. The model coefficients were determined for drying air temperatures of 40, 45, 50 and 55°C. It was found that the predicted and experimental data agreed satisfactorily with R2 and RMSE values of 0.9225-0.9786 and 0.0325-0.0750 respectively. A computer simulation model was developed to predict moisture ratio at a given drying time.
American Journal of Food Science and Technology. 2017, 5(3), 93-100. DOI: 10.12691/ajfst-5-3-4
Pub. Date: May 25, 2017
14173 Views2768 Downloads
by Olaoluwa Ruth Obisesan, Abolanle Saheed Adekunle, John Adekunle Oyedele Oyekunle, Efere Martins Obuotor, Olatunji Seyi Ojo, Adedayo Muideen Sanni, Muib Adewale Akinyemi and Oyedare Mayowa Adesina
Original Research
This study examined the effect of refining process on physicochemical properties of used vegetable oils from two restaurants in Ile-Ife Nigeria, and their biodiesel potential using biological and chemical based heterogeneous catalyst. The refining stages are degumming, alkaline treatment and bleaching. Physicochemical properties of both refined and the used oils were carried out using the AOAC methods. Transesterification of biodiesel was carried out using KOH and plantain peel as the catalyst, while the fuel properties of the biodiesel obtained were determined using ASTM methods. Results showed that the biodiesels obtained from the used vegetable oils using environmental friendly and readily available catalyst, were better substitute with cheap cost of production compared with biodiesel fuel produced from normal vegetable oils. Also, the refining processes showed that the refined oils have gained better industrial application with improved physicochemical properties after each refining stages.
American Journal of Food Science and Technology. 2017, 5(3), 78-88. DOI: 10.12691/ajfst-5-3-2
Pub. Date: May 18, 2017
15076 Views3134 Downloads3 Likes
by Mahamadou Elhadji Gounga, Khamis Ali Omar, Issoufou Amadou and Shi-Ying Xu
Original Research
Chestnuts are characterized by a limited shelf-life because of their high water content and sugar content hence producers around the world are confronted with a storage problem as product losses are very high. The strategy of the conception, stemming from the current adoption of new food technologies combined with the consumer desirability to put to shelf new products on the market has made researchers and industrialists to upgrade and/or add value to the existing products in order to provide a wider choice of new products to the consumer disposal. The objective of this work was to come up with a suitable technology of extending the shelf-life of harvested chestnut fruits and to develop a new food product for commercial consumption. Whey protein isolate–Pullulan-coated roasted and freeze-dried chestnut (WPI–Pul-RFDC) was coated separately with dark chocolate (DCC) and milk chocolate (MCC). Color change of surface coating and decay incidence were studied at [7°C, 82 ± 5% RH] and [25 ± 2°C, 30 ± 2% RH] for 6 months storage. Further investigation on sensory evaluation were carried out using a taste panel of 120 consumers. 7°C and 25°C provided the best storage conditions for dark chocolate and milky chocolate coating respectively. The results obtained were effective in the control of overgrowth of spoilage organisms and surface discoloration, which is satisfactory in improving the quality and increasing the shelf-life of chestnut. The consumer acceptance testing revealed that chocolate-coating greatly improved the sensory attributes of chestnut as compared to the WPI-Pul coated sample acceptance. This is an alternative strategy to add value to chestnut thus minimizing the significant losses in harvested fruits hence providing a wider choice of new products to the consumer disposal.
American Journal of Food Science and Technology. 2017, 5(3), 70-77. DOI: 10.12691/ajfst-5-3-1
Pub. Date: May 11, 2017
11152 Views2790 Downloads1 Likes