Department of Biotechnology and Food Science, Norwegian University of Science and Technology, NTNU, 7491, Trondheim, Norway.
SINTEF Sealab, Brattørkaia 17 C, 7010, Trondheim, Norway.
BMC Biotechnol. 2020 May 6;20(1):22. doi: 10.1186/s12896-020-00618-x.
In Norway, 3 million discarded egg-laying hens are destructed annually, which equals 1500 tons pure hen meat. Due to the slaughter methods used, this raw material is handled as a high-risk waste, while in reality it constitutes a source of valuable components like proteins and lipids.
This study assess different processing methods (thermal treatment, enzymatic hydrolysis and silaging) for utilization of discarded egg-laying hens for the production of ingredients for human consumption and animal feed. The processing methods were evaluated on the basis of quantity and quality of the obtained products.
Thermal treatment and enzymatic hydrolysis resulted in extraction of good quality lipids from the raw material. The separated oil (50.1-82.3% of the total lipid content in the raw material) was of high quality based on the content of free fatty acids (≤ 1.0%) and total oxidation value (≤ 3.9). Enzymatic hydrolysis also enabled separation of protein in the form of protein hydrolysate. Addition of Protamex and Papain+Bromelain significantly (p ≤ 0.05) increased the protein content (85.1-94.6%) and decreased the lipid content (0.3-1.1%) in the hydrolysate compared to autolysis (protein content: 64.8-72.3%, lipid content: 1.0-2.6%). Silaging increased the protein digestibility (63.2-79.7% compared to 57.3-66.2% for untreated raw material), and thus constitutes a good method for utilizing the protein content of the raw material for animal feed.
The biotechnological processing methods thermal treatment, enzymatic hydrolysis and silaging can be used to increase the utilization of discarded egg-laying hens for production of ingredients for human consumption and animal feed.
在挪威，每年有 300 万只淘汰蛋鸡被销毁，相当于 1500 吨纯鸡肉。由于所采用的屠宰方法，这种原材料被视为高风险废物，而实际上它是蛋白质和脂质等有价值成分的来源。
本研究评估了不同的加工方法（热处理、酶解和青贮），以利用淘汰蛋鸡生产供人类食用和动物饲料的成分。根据获得的产品的数量和质量对加工方法进行了评估。
热处理和酶解从原料中提取出高质量的脂质。分离出的油（占原料总脂质含量的 50.1-82.3%）质量很高，游离脂肪酸含量（≤1.0%）和总氧化值（≤3.9）都很低。酶解还可以分离出蛋白质水解物形式的蛋白质。添加 Protamex 和 Papain+Bromelain 可显著（p≤0.05）提高水解产物中的蛋白质含量（85.1-94.6%）并降低脂质含量（0.3-1.1%），与自溶相比（蛋白质含量：64.8-72.3%，脂质含量：1.0-2.6%）。青贮可提高蛋白质消化率（与未处理原料相比，63.2-79.7%），因此是利用原料中蛋白质生产动物饲料的好方法。
生物技术处理方法热处理、酶解和青贮可用于提高淘汰蛋鸡的利用率，以生产供人类食用和动物饲料的成分。
