ABSTRACT
The aim of this study was to evaluate the impact of cooking conditions on proximate composition and textural properties (cohesiveness and chewiness) of chicken breast meat. Eight packs of industrial skinless chicken breast meat were cooked by air frying (AF), baking (BK), deep fat frying (DF) and grilling (GR) at 170, 180 and 190oC for 0, 4, 8, 12 and 16 min. The chicken breast packs were frozen and sliced into dimensions, thawed, cooked and analysed by a two way analysis of variance. The results revealed that cooking methods significantly (p < 0.05) decreased moisture and protein contents from 75.14 to 58.25 % and 89.17 to 82.98 %, but increased fat content from 4.26 to 7.78 %, ash content from 1.95 to 2.39 %, carbohydrate content from 4.63 to 6.95 %, cohesiveness content from 0.40 to 0.52 and chewiness value from 3.63 to 6.05 kg. An increases in cooking temperatures and times decreased moisture content from 60.58 to 56.34 % and 75.14 to 47.40 % and protein content from 83.77 to 82.11 % and 89.17 to 79.45 %. Similarly, increases in cooking temperatures and times significantly (p < 0.05) increased fat content from 7.00 to 8.44 % and 4.26 to 10.12 %, ash content from 2.15 % to 2.59 % and 1.95 to 2.67 %. This study showed that increases in cooking temperatures decreased non-significantly (p > 0.05) carbohydrate content from 7.02 to 6.92 %, but increases in cooking times increased carbohydrate content from 4.63 to 7.76 %. An increases in cooking temperatures and times increased cohesiveness content from 0.50 to 0.54 and 0.40 to 0.63, chewiness value from 5.50 to 6.77 kg and 3.63 to 8.54 kg, respectively. There were no significant differences (p > 0.05) in chewiness values of samples cooked by AF and GR methods. The best cooking method/ temperature / time for low nutrient losses was BK, 170oC and 4 min
ABSTRACT
The study was conducted to ascertain the effect of thermal treatments on selected minerals (Ca, K, Mg, Na, P, Fe and Zn) and water soluble vitamins (B1, B2, B3, B6, B9, B12 and C) contents of chicken breast meat. Industrial skinless chicken breast meat samples were purchased, transported to Bioprocess laboratory in cool conditions, frozen and sliced into dimensions and thawed. The samples were cooked by air frying (AF), baking (BK), deep fat frying (DF) and grilling (GR) at 170, 180 and 1900C for 0, 4, 8 and 12 min for minerals and 0, 8 and 16 min for vitamins. Thereafter, cooked and raw samples were wet acid digested overnight and 5 h digested on a block digester on slowly increased temperature to 1200C, cooled and deionized. The mineral elements were analysed by Optima 4300DV inductivity coupled plasma optical emission spectrometry (ICP-OES) and inductivity coupled plasma mass spectrometry (ICP-MS). These mineral elements were extrapolated through a calibration curve between intensity and concentration, while the vitamins were ascertained by measurement of absorbance of filtrates of the samples dissolved in their respective solvents in the Spectrophotometer against their blank samples at different wavelengths. The results showed that cooking methods decreased significantly (p < 0.05) the mineral elements with an exception of Zn cooked by grilling (GR) that increased by 19.92% and Mg that increased in the cooking methods. The ascending percentage reduction of minerals in cooked chicken breast were Zn, P, K, Fe, Na and Ca. Samples cooked by DF had significantly (p < 0.05) higher percentage reduction of 45.06% in Ca, 27.74% in Na and 18.85% in Zn and higher percentage increases of 14.96% in Mg contents than other methods. Also samples cooked by DF had higher percentage reductions of 55.10%, 37.93%, 37.11%, 34.44% and 30.99% in vitamins B1, C, B2, B9 and B6 Whereas higher percentage reductions of 41.67% and 37.84 % in vitamins B12 and B3 occurred in baking (Bk) and grilling (GR) treated samples. Cooking at 1900C had higher percent reduction in the Ca, Na, Fe, K, P and Zn as well as B1, B12, B2, C, B3, B9 and B6. Cooking methods, temperatures and times decreased significantly (p < 0.05) vitamins and minerals contents of chicken breast meat with an exception of Mg. Samples cooked at 1700C for 4 min and 1700C for 8 min had lower losses of minerals and vitamins compared to similar samples cooked at 1800C and 1900C. The AF cooking method had the least percent reduction of 22.50% than other cooking methods BK (26.88%), DF (36.04%) and GR (30.69%) in vitamin contents.
ABSTRACT
The effect of cooking on pH, juiciness, instrumental colour and microstructural properties of chicken breast meat was investigated. Industrial skinless chicken breast meat samples were purchased, frozen and sliced into dimensions , thawed and cooked by air frying (AF), baking (BK), deep fat frying (DF) and grilling (GR) at 170, 180 and 1900C for 0, 4, 8, 12 and 16 min. The pH value of the cooked samples increased from 6.05 to 6.25. Cooking methods, temperatures and times each resulted to increase in pH. The results of objective sensory instrumental analyses showed that cooking decreased significantly (p < 0.05) juiciness of cooked chicken breast meat. Samples cooked by BK had the highest juiciness value of 24.91%, while DF cooked samples had the least value of 13.89%.The instrumental analyses increased L*, a*, b* values and browning index. The temperature and time of cooking showed similar effects on juiciness and instrumental colour. Short cooking time (8 min) and 1700C resulted in higher juiciness and best appetizing appearance to the consumers. The microstructure studies showed that raw chicken breast meat had an intact muscle fibres and bundles, but cooking caused disintegration of muscle fibres, perimysial – collagen shrinkage and it resulted to drier samples with big cracks/ voids and big surface damages, particularly in AF, BK and GR cooked products at 1900C for 8 min.