Mohammadnezhad Sedigheh, Farmani Jamshid
Department of Food Science and Technology Faculty of Agricultural Engineering Sari Agricultural Sciences and Natural Resources University Sari Iran.
Food Sci Nutr. 2022 Apr 19;10(6):1908-1920. doi: 10.1002/fsn3.2807. eCollection 2022 Jun.
Chicken skin is a major byproduct of the poultry industry. This study was undertaken to extract and characterize fat and gelatin from chicken skin. To do this, the chicken skin was wet-rendered at different temperature-time combinations and the yield and properties of the extracted gelatin and fat were determined. Gelatin and fat were recovered at yield ranges of 0.74%-2.03% and 24.01%-27.91%, respectively. The time and the interaction of time-temperature had a positive effect on gelatin yield ( < .05); however, the fat yield was not affected by the extraction condition. Protein, ash, and hydroxyproline content of gelatin and unsaponifiables and free fatty acids contents, peroxide value, and induction period of oxidation of the fat were affected by the extraction condition. Functional and rheological analyses showed chicken skin gelatin gel/solution had a higher bloom value, viscosity, foaming capacity, storage and loss moduli, and melting and gelling points than the commercial bovine gelatin. Oleic (42.13%), palmitic (24.6%), and linoleic (17.53%) acids were the main fatty acids of chicken skin fat. The storage modulus of chicken skin fat was higher than the loss modulus up to 31°C; however, because of a low slip melting point (22.74°C) and solid fat content, it was fluid at room temperature. The findings of this research can be useful in the development of processes for the extraction and application of chicken skin gelatin and fat.
鸡皮是家禽业的一种主要副产品。本研究旨在从鸡皮中提取脂肪和明胶并对其进行表征。为此，将鸡皮在不同的温度 - 时间组合下进行湿法熬制，并测定提取的明胶和脂肪的产率及性质。明胶和脂肪的回收率分别在0.74% - 2.03%和24.01% - 27.91%的范围内。时间以及时间 - 温度的相互作用对明胶产率有积极影响（P < 0.05）；然而，脂肪产率不受提取条件的影响。提取条件会影响明胶的蛋白质、灰分和羟脯氨酸含量，以及脂肪的不皂化物和游离脂肪酸含量、过氧化值和氧化诱导期。功能和流变学分析表明，鸡皮明胶凝胶/溶液的勃氏值、粘度、发泡能力、储能模量和损耗模量以及熔点和胶凝点均高于市售牛明胶。油酸（42.13%）、棕榈酸（24.6%）和亚油酸（17.53%）是鸡皮脂肪的主要脂肪酸。鸡皮脂肪的储能模量在31°C以下高于损耗模量；然而，由于其低滑移熔点（22.74°C）和固体脂肪含量，在室温下呈液态。本研究结果可有助于开发鸡皮明胶和脂肪的提取及应用工艺。
