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| 特异性定量测定油脂和含油食品酸价的新铜皂比色法 |
| Cupric acetate-pyridine colorimetric method for specific quantitative determination of acid value of oils，fats and oily foodstuffs |
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| DOI： |
| 中文关键词: 酸价 铜皂比色法 酸碱滴定 游离脂肪酸 食用油脂 含油食品 |
| 英文关键词:acid value cupric acetate-pyridine colorimetric method acid-base titration free fatty acid edible oils and fats oily foodstuffs |
| 基金项目:食品安全国家标准制修订项目（spaq-2020-40） |
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| 中文摘要: |
| 建立了一种可特异性测定食用油脂及含油食品中游离脂肪酸（FFA）的新铜皂比色法。优化了铜皂比色法的最佳测定波长，研究了有机相溶剂对显色强度和油脂溶解稳定性的影响，以及不同种类FFA对铜皂反应显色强度的影响。此外，研究了食用油脂样液水洗、酸性食品添加剂和酸性食用香精香料对铜皂比色法测定的影响。结果表明：新铜皂比色法的最佳测定波长为710 nm，环己烷是理想的有机相溶剂；新铜皂比色法能有效排除酸性食品添加剂等非FFA的酸性物质干扰；该法采用油酸显色，外标法定量，可实现0.1~5.0 mg/g的液态油和0.2~10.0 mg/g的固态脂酸价的定量测定；对于无酸性物干扰的食用油脂，其测定结果与传统酸碱滴定法相关性良好（R2>0996），回收率为91.3%~93.8%，重复性实验相对标准偏差小于3%，单次测定仅需1 g油脂样品。因此，新铜皂比色法是一种准确而便捷的酸价测定技术，适用于油脂和含油食品的酸价测定。 |
| 英文摘要: |
| A new cupric acetate-pyridine colorimetric method used for specific determination of FFA in oils, fats and foodstuffs was established. The optimal detection wavelength of the new method was optimized, the effects of solvents on the color intensity and the solubility stability of oils and fats were studied, and the effects of different kinds of FFA on the color intensity were also studied. In addition, the influences of edible oil sample washing, acidic food additives and acidic food flavors on the determination of the new method were also studied. The results showed that the best detection wavelength was 710 nm, and cyclohexane was the ideal solvent. Cupric acetate-pyridine colorimetric method could effectively eliminate the interference of acidic food additives and other non-FFA acids. The determination of acid value in liquid oil (0.1-5.0 mg/g) and solid fat (0.2-10.0 mg/g) was achieved by using oleic acid as colorimetric calibration. For edible oils without acid interference, the detection results correlated well with the traditional acid-base titration method (R2＞0.996). Overall, the recovery was 913%-93.8% and the relative standard deviation of reproducibility test was less than 3%. Each test only required 1 g of oil and fat sample. In conclusion, the cupric acetate-pyridine colorimetric method served as an efficient, accurate, and convenient alternative for the determination of acid values of oils, fats, and foodstuffs as well. |
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