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Full-Text Articles in Food Science

Optimization Of Biodiesel Production From Crude Cottonseed Oil And Waste Vegetable Oil:Conventional And Ultrasonic Irradiation Methods, Xiaohu Fan Dec 2008

Optimization Of Biodiesel Production From Crude Cottonseed Oil And Waste Vegetable Oil:Conventional And Ultrasonic Irradiation Methods, Xiaohu Fan

All Dissertations

Biodiesel, derived from the transesterification of vegetable oils or animal fats with simple alcohols, has attracted more and more attention recently. As a cleaner burning diesel alternative, biodiesel has many attractive features including: biodegradability, nontoxicity, renewability and low emission profiles.
Although cottonseed oil was the first commercial cooking oil in the U.S, it has progressively lost its market share to some vegetable oils that have larger production and less cost. However, regarding the active researches on biodiesel production from vegetable oils, there is a promising prospective for the cottonseed oil as a feedstock for biodiesel production, which may enhance the …


Modelling Tempering Behaviour Of Dark Chocolates From Varying Particle Size Distribution And Fat Content Using Response Surface Methodology, Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, Joselio Vieira Sep 2008

Modelling Tempering Behaviour Of Dark Chocolates From Varying Particle Size Distribution And Fat Content Using Response Surface Methodology, Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, Joselio Vieira

Professor Emmanuel Ohene Afoakwa

Central Composite Rotatable Design (CCRD) for K=2 was used to study the combined effects of multi-stage heat exchangers for Stages 1 (14–30 °C) and 2 (12–28 °C) coolant temperatures at constant Stage 3 coolant and holding temperatures during tempering of dark chocolates using laboratory-scale mini-temperer. Quantitative data on chocolate temper index (slope) were obtained for products with varying particle size distribution (PSD) (D90 of 18, 25, 35 and 50 μm) and fat (30% and 35%) content. Regression models generated using stepwise regression analyses were used to plot response surface curves, to study the tempering behaviour of products. The results showed …


Optimisation Of Steamer Jet-Injection To Extend The Shelf Life Of Fresh-Cut Lettuce, Daniel Rico, Ana Belen Martin-Diana, Catherine Barry-Ryan, Gary Henehan, J. Barat, Jesus Maria Frias Jan 2008

Optimisation Of Steamer Jet-Injection To Extend The Shelf Life Of Fresh-Cut Lettuce, Daniel Rico, Ana Belen Martin-Diana, Catherine Barry-Ryan, Gary Henehan, J. Barat, Jesus Maria Frias

Articles

Optimisation of short time blanching (steaming) was investigated using response surface methodology by analysing quality and microbial and nutritional markers over the shelflife of packaged fresh-cut lettuce. Steamer treatment time (5–10 s) and storage (1–10 days) were used as independent factors in order to optimise the process. Longer treatments (>10 s) were not feasible because of extensive damage caused to lettuce tissue. Significantly (p < 0.05) higher values of luminosity (L*), greenness (−a*) and sensory panel scores (fresh appearance, general acceptability and absence of browning) were obtained with samples treated for longer times with the steamer. Activity of browning-related enzymes present in photosynthetic tissue decreased in all the cases, however, longer treatment time (7.5–10 s) was needed with vascular tissues to reduce to similar activity values. These differences could be explained by the variation in tissue thickness. The longest steam treatment (10 s) reduced and maintained significantly (p < 0.05) lower mesophilic load than shorter treatments (5–8.5 s). However, significant (p < 0.05) decreases in vitamin C and carotenoids were observed in samples treated with longer treatments. Steamer treatment of 10 s could be considered the optimum time for maintaining the shelflife (mainly texture and browning) of fresh-cut lettuce for 7–10 days in optimum conditions.