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J Food Sci Technol (NovemberDecember 2013) 50(6):11511157 DOI 10.1007/s13197-011-0439-4
ORIGINAL ARTICLE
Effects of microwave rendering on the yield and characteristics of chicken fat from broiler abdominal fat tissue
Liyan Zhang & Bi Yin & Hanming Rui
Revised: 2 June 2011 /Accepted: 16 June 2011 /Published online: 29 June 2011 # Association of Food Scientists & Technologists (India) 2011
Abstract Microwave rendering process and effects of rendering conditions on yields and characteristics of chicken fat from broiler abdominal fat tissue were studied. Microwave rendering process could be divided into three phases: warming-up, constant temperature and heating-up phases. Increasing microwave power increased the rate of temperature rise and final temperature of chicken fat, shortened the duration of warming-up and constant temperature phase, and decreased the moisture content of chicken fat. Longer irradiation time resulted in higher final temperature, lower moisture content and darker, browner color of chicken fat. The chicken fat rendered at power level of 2.75 W/g for 10 min had the highest yield (70.55%) with the lowest peroxide value, acid value and thiobarbituric acid value (p<0.05). The major fatty acids in chicken fat obtained at optimum conditions were oleic acid (45.73%), palmitic acid (26.13%), linoleic acid (15.12%), palmitoleic acid (6.07%), and stearic acid (5.81%).
Keywords Broiler abdominal fat . Microwave rendering . Process . Yield . Characteristic
Introduction
Chicken fat can be used as cooking oil to increase the taste of dishes or as raw materials to manufacture chicken powder (Lin 1998) and biodiesel fuel (Ding et al. 2007). In food industry, chicken fat is usually rendered from chicken depot fat tissue including abdominal fat tissue or skin fat (Li and Bi 2009) etc.
Rendering can refer to the processing of whole animal fatty tissue into purified fats like lard or tallow. There are various rendering methods, including dry rendering, wet rendering and frying (Hui 2001; Pereira et al. 1976; Sheu and Chen 2002). Nowadays, wet rendering is more popular than dry rendering in industry and the fat yielded has less free fatty acids (Hui 2001). It is more energy efficient and allowed the re-use of process vapors to pre-heat or dry the materials during the process. But the production and separation of emulsion layer are the main problems affecting the application of wet rendering....