DSpace Collection: Thesis - Food Engineering

EVALUATION OF CHEDDAR AND COTTAGE CHEESE PRODUCTION FROM DOE AND EWE MILK

Tue, 02 Apr 2013 05:36:43 GMT

Title: EVALUATION OF CHEDDAR AND COTTAGE CHEESE PRODUCTION FROM DOE AND EWE MILK

Authors: Bezaye, Taye

Abstract: The study was aimed to produce cheddar and cottage cheese from doe and ewe milk. The sources of milk were from Arsi Negele and Kofele areas of Oromiya region. Cheddar cheeses were made from whole doe, whole ewe milk and their mixtures contained ratio of 25, 50 and 75% of doe and ewe milk using standard procedure for cheddar cheese processing technology. The proximate, microbiological, Physico-chemical, sensory analysis and yield calculation of the cheeses were made at chemical Engineering laboratory, Holleta agricultural research center, Ethiopian health and nutrition research institute.The proximate analysis result showed that cheeses made from 100% doe milk had the lowest moisture content (27.77%) and highest fat content (54.80%) but a lower yield (0.66kg/5kg of whole milk) compared to cheeses made from 100% ewe milk (35.29%, 30.1%, 0.88kg/5kg of whole milk respectively). Other mix ratios had intermediate values between the two specious of cheese (p<0.05). No significant differences in the values of protein, total solid and lactose content of sampled cheeses were found. Microbiological results showed that all cheeses made were within the limit range for acceptable conditions for consumers (< 1* 104 cfu/g). Physico – chemical analysis result showed that whole ewe milk had highest viscosity of all cheeses (3.04mPas). Three main stage of cheddar cheese making was considered for pH measurement. These stages were ripening, cooking and cheddaring. The decrease in pH was most rapid in 100% doe milk and slowest in that of 100% ewe milk. Textural analyses result showed that cheese made from 100% doe milk was harder (0.65 N/g) and less brittle than those from their combination. The cheese from 100% ewe milk is the softest (0.30 N/g) compared to mix ratios and whole doe milk. Sensory analysis result showed that cheeses made from 50% ewe and 50% doe milk received, in general higher scores for body texture (8.94), flavor (8.81) and overall acceptability (8.98) than cheeses from whole and their combinations (p<0.05). The mean yield of cottage cheese was 0.33kg/ 2kg of whole milk and 0.45kg/ 2kg of whole milk for 100% doe milk and 100% ewe, respectively. From over all analysis the best acceptable and quality cheese was obtained from mix ratio of 50% ewe and 50% doe milk. The thesis generally includes processing technology and evaluation of cheddar cheese made from doe and/or ewe milk. As a result an economically feasible production system has been recommended by scaling up to industry level.

EFFECT OF PROCESSING ON PHYTOCHEMICALS AND NUTRIENTS COMPOSITION OF FENUGREEK (TRIGONELLA FOENUM-GRAECUM L.), AND DEVELOPMENT OF VALUE ADDED PRODUCTS

Tue, 05 Feb 2013 04:59:24 GMT

Title: EFFECT OF PROCESSING ON PHYTOCHEMICALS AND NUTRIENTS COMPOSITION OF FENUGREEK (TRIGONELLA FOENUM-GRAECUM L.), AND DEVELOPMENT OF VALUE ADDED PRODUCTS

Authors: Birhane, G/Silassie

Abstract: The primary purpose of this research was to study the effects of germination, fermentation, autoclaving, extraction and their combinations on the phytochemicals and nutrients composition of fenugreek seed varieties (Challa, Ada’a and Wello). The chemical compositions, physico-chemical and functional properties, mineral bioavailability, and phytate and non phytate phosphorus contents of fenugreek seeds were investigated. Furthermore, during polar solvent extraction process, the influences of rinsing stages, solvent type, and proportion of solvent to water on the rate of extraction were also examined. The average mean value on dry weight basis of fenugreek’s moisture content was 7.5%, crude protein 29.3%, crude fat 7.9%, crude, fiber 7%, total ash 3% and total carbohydrates 45.2%. The major mineral constituents of fenugreek seeds were K (10351.7 mg/kg), P (5651.3 mg/kg), Mg (1257.3 mg/kg) and Na (121.5 mg/kg), Ca (553.7 mg/kg), Fe (81.3 mg/kg) and Zn (43.4 mg/kg). Saponins, phytates and tannins concentrations ranged from 4581.3 to 6320.8, 76.11to 111.08 and 235.24 to 269.13mg/100g; respectively. Water and oil absorption capacities were 7.5, 10.2 & 7.2 g/g of water and 1.04, 1.12 & 2.3g/g of oil absorption capacity for Challa, Ada’a and Wello; respectively. Crude protein, fat, fiber, mineral bioavailability and non phytate phosphorus compositions were improved during processing methods. Significant reduction of phytochemicals was achieved by employing conventional, heat and chemical processing methods. Germination reduced phytates, tannins, and saponins by 47.9 – 66.4%, 33.7 – 56.8%, & 46.3 – 69.9%, fermentation 68.7 – 100%, 40.7 – 87.9% & 67.8 – 81.0%, autoclaving 32.5 – 36.4%, 66.4 – 74.7%, & 88.6 – 94.6% and extraction 6.7 – 7%, 100%, & 100%; respectively. Extraction was less effective in reducing phytates as compared to other processing methods due to insolubility of phytates in alcohol (ethanol &methanol). The combination of germination and fermentation resulted in a significant and successive reduction in phytates, tannins and saponins levels. However, complete removal of all phytochemicals was achieved by the combination of fermentation followed by extraction process. During extraction, as the proportion of water increases the percolation rate decreases due to water binding property of fenugreek. Methanol extraction was faster and powerful than ethanol extraction. The extraction process also removed the astringent smell and bitterness of fenugreek. Thus, debitterized fenugreek powder was produced. In addition, to preserve the health benefits and to maintain dose of fenugreek required for different age groups, sex and health conditions, fenugreek capsules were also produced.

Development and Evaluation of Chickpea and Rice Based Dry Fermented Sausages

Thu, 17 Jan 2013 08:07:37 GMT

Title: Development and Evaluation of Chickpea and Rice Based Dry Fermented Sausages

Authors: Habtamu, Asmare

Abstract: This research study was conducted with the aim of development and evaluation of chickpea and rice based dry fermented sausages. The dry fermented sausages were prepared through blending of meat with chickpea and rice flours, sodium chloride, sodium nitrite, garlic, and starter culture according to the basic formulation for sausage production. The effect of fermentation time (24h and 48h), blending of chickpea and rice flours (20% and 30% each), and drying time (7days and 12days) on proximate composition, color, pH and lactic acid values, sausage yields, microbial load, and sensory qualities of the dry fermented sausages were investigated. The ranges for proximate composition of chickpea and rice based dry fermented sausages in (%) were for moisture (25.36 – 30.16 and 24.57 – 31.06), crude protein (29.13 – 31.88 and 20.89 – 27.07), crude fat (17.45 – 23.12 and 15.27 – 19.84), crude fiber (2.68 - 3.38 and 1.62 – 3.48), total ash (6.00 – 7.72 and 5.46 – 7.47), total carbohydrates (11.83 – 16.67 and 20.53 – 27.72) and energy value (338.62 - 385.47 and 321.65 - 380.78kcal/100g); respectively. The mineral components of the dry fermented sausages were significantly (p<0.05) increased as compared to sausage batters. Sodium was the most abundant over other minerals due to the addition of NaCl and NaNO2 salts in sausages processing technology. The processing parameters resulted decrease in pH and rise in lactic acid values which, were more significant (p<0.05) during the 48h fermentation and 7days of drying. The blending level of chickpea and rice flours had effect on color of dry fermented sausages which had revealed higher L* and b* values and lower a* value compared to the control. Higher sausage yields were obtained from the dry fermented sausages processed by blending of chickpea flour and rice flour at 30% blending ratio, 24h fermentation and 7 days drying. Microbiological results showed significant (p<0.05) amount of reduction of undesirable and increment of desirable microbes with in processing parameters. Total lactic acid bacteria were found to be the predominant micro flora of the final products and reached more than 8.5 log cfu/g, however, Enterobacteriaceae were not detected. The sensory quality results indicated that chickpea and rice based dry fermented sausages with 20% blending ratio revealed acceptable range of the hedonic scale. In general, the dry fermented sausages processed by blending of meat with 20% chickpea flour and 20% rice flour, fermented for 48h and dried for 12days gave the promising results. Based on the preliminary techno-economic evaluation, the suggested process technology and product diversification is feasible.

Development and Evaluation of Chickpea and Rice Based Dry Fermented Sausages

Thu, 17 Jan 2013 07:43:34 GMT