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Acid value (AV) serves as an important indicator to assess the quality of oil, which can be used to judge the deterioration of edible oil. In order to realize the quantitative prediction of the AV of camellia seed oil, which was made from camellia oleifolia, hyperspectral data of 168 camellia seed oil samples were collected using a hyperspectral imaging system, which were related to their AV content measured via classical chemical titration. On the basis of hyperspectral full wavelengths, characteristic wavelengths, and fusing spectral and image features, the quantitative prediction AV models for camellia seed oil were established. The results demonstrating the 2Der-SPA-GLCM-PLSR model fusing spectral and image features stood out as the optimal choices for the AV prediction of camellia seed oil, with the correlation coefficient of calibration set ( R c 2 ) and the correlation coefficient of prediction set ( R p 2 ) at 0.9698 and 0.9581, respectively. Compared with those of 2Der-SPA-PLSR, the R c 2 and R p 2 were improved by 2.11% and 2.57%, respectively. Compared with those of 2Der-PLSR, the R c 2 and R p 2 were improved by 5.02% and 5.31%, respectively. Compared with the model based on original spectrum, the R c 2 and R p 2 were improved by 32.63% and 40.11%, respectively. After spectral preprocessing, characteristic wavelength selection, and fusing spectral and image features, the correlation coefficient of the optimal AV prediction model was continuously improved, while the root mean square error was continuously decreased. The research demonstrated that hyperspectral imaging technology could precisely and quantitatively predict the AV of camellia seed oil and also provide a new environmental method for detecting the AV of other edible oils, which is conducive to sustainable development. [ABSTRACT FROM AUTHOR]

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Acid and peroxide values are important indicators to evaluate the hydrolysis or oxidation level of vegetable oil. In order to achieve rapid determination of these parameters by Raman spectroscopy, rapeseed and soybean oil were analyzed, and a competitive adaptive reweighted sampling-back propagation neural network (CARS-BPNN) method was developed. First, the Raman spectrum was preprocessed to reduce noise using moving window smoothing. Next, competitive adaptive reweighted sampling (CARS), successive projections algorithm (SPA), and uninformative variable elimination (UVE) was applied to extract the Raman characteristic information that indicated the acid and peroxide values. Based on the extracted characteristic information, back propagation neural network (BPNN), partial least squares regression (PLSR), and support vector machine (SVM) prediction models were established and compared. The results showed that the best accuracy was obtained using CARS-BPNN. For rapeseed oil, the coefficients of determination (R2) of acid value and peroxide value were 0.9207 and 0.9772. The root mean square error (RMSE) values were 0.0909 and 0.0022, respectively. For soybean oil, the coefficients of determination (R2) of acid and peroxide values were 0.9381 and 0.9716. The RMSE values were 0.1250 and 0.0027, respectively. A good correlation coefficient and a small RMSE value were obtained. The results indicate that Raman spectroscopy combined with CARS-BPNN accurately evaluated the acid and peroxide values, which provides a reference for the optimization of the Raman spectrum and creates a new approach for the evaluation of vegetable oil quality. [ABSTRACT FROM AUTHOR]

Copyright of Výživa a Potraviny is the property of Spolecnost pro Vyzivu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

为了更好地对小磨芝麻香油进行质控，在芝麻焙炒、石磨磨浆、水墩油3个主要工艺过程结束时取样，对不同工艺阶段芝麻油的色泽、酸值、过氧化值、脂肪酸组成及风味进行了检测。结果表明：水墩油过程使芝麻油有最大的a值和b值，分别为12.84和89.36；焙炒和石磨磨浆过程芝麻油的酸值不断降低，经水墩油之后又有所上升；与未焙炒的芝麻油相比，焙炒使芝麻油的多不饱和脂肪酸含量略有增加；电子鼻检测结果与GC-MS结果一致，焙炒和石磨磨浆过程所得芝麻油的风味相似，而水墩油使芝麻油风味物质种类增多，风味更强。综上，除焙炒过程外，水墩油也是影响小磨芝麻香油品质，特别是色泽和风味的关键环节，应加强对该阶段小磨芝麻香油风味物质变化与形成的研究。 In order to better control the quality of ground fragrant sesame seed oil, the color, acid value, peroxide value, fatty acid composition and flavor of sesame seed oil in different process stages were measured by sampling at the end of three main processes: sesame seed roasting, millstone grinding and oil separation by oscillation (including water adding and mixing). The results showed that the process of oil separation by oscillation made sesame seed oil have the largest a value and b value, which were 12.84 and 89.36, respectively. The acid value of sesame seed oil decreased continuously during roasting and millstone grinding, but increased after oil separation by oscillation. Compared with sesame seed oil obtained with unroasted sesame seed, roasting increased the polyunsaturated fatty acids content slightly. The results of electronic nose detection were consistent with those of GC-MS. The flavor of sesame seed oil obtained by roasting and millstone grinding was similar, while the variety of flavor substances in sesame seed oil increased and the flavor was stronger after oil separation by oscillation. In conclusion, besides the roasting process, oil separation by oscillation is also a key link that affects the quality of ground fragrant sesame seed oil, especially the color and flavor. It is necessary to strengthen the research on the change and formation of flavor substances in ground fragrant sesame seed oil at this stage.

为了筛选出适合辣椒鸡油的天然抗氧化剂，以延长其保质期，研究并比较了6种天然抗氧化剂（迷迭香提取物、维生素E、茶多酚、维生素C、槲皮素和硫辛酸）对辣椒鸡油酸值、过氧化值、DPPH自由基清除能力和总还原能力的影响。结果表明：6种天然抗氧化剂在辣椒鸡油中均具有一定的抗氧化能力；在抑制酸值方面，槲皮素效果最佳，维生素C最差;在抑制过氧化值方面，槲皮素效果最佳，维生素E最差；在DPPH自由基清除能力方面，迷迭香提取物效果最佳，硫辛酸最差；在总还原能力方面，槲皮素效果最佳，维生素E最差；槲皮素、迷迭香提取物和茶多酚在酸值、过氧化值、DPPH自由基清除能力和总还原能力方面均位于前三。综合考虑抗氧化效果、抗氧化剂稳定性、成本等因素，可优先选择迷迭香提取物和茶多酚作为辣椒鸡油的抗氧化剂以提高其储藏性能。In order to screen natural antioxidants suitable for chili chicken oil and extend its shelf life, the effects of six natural antioxidants (rosemary extract, vitamin E, tea polyphenols, vitamin C, quercetin and lipoic acid) on the acid value, peroxide value, DPPH radical scavenging capacity, and total reducing capacity of chili chicken oil were investigated and compared. The results showed that six natural antioxidants had certain antioxidant capacity in chili chicken oil; in inhibiting acid value, quercetin was the most effective and vitamin C was the worst; in inhibiting peroxide value, quercetin was the best and vitamin E was the worst; in terms of DPPH radical scavenging capacity, rosemary extract was the most effective and lipoic acid was the worst; in terms of total reducing capacity, quercetin was the most effective and vitamin E was the worst. Quercetin, rosemary extract and tea polyphenols were in the top three in terms of acid value, peroxide value, DPPH radical scavenging capacity and total reducing capacity. Considering the antioxidant effect, antioxidant stability and cost, rosemary extract and tea polyphenols can be preferred as antioxidants for chili chicken oil to improve its storage performance.

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Palm oil has a bad reputation due to the exploitation of farmers and the destruction of endangered animal habitats. Therefore, many consumers wish to avoid the use of palm oil. Decorative sugar contains a small amount of palm oil to prevent the sugar from melting on hot bakery products. High-oleic sunflower oil used as a substitute for palm oil was analyzed in this study via multispectral imaging and an electronic nose, two methods suitable for potential large-batch analysis of sugar/oil coatings. Multispectral imaging is a nondestructive method for comparing the wavelength reflections of the surface of a sample. Reference samples enabled the estimation of the quality of unknown samples, which were confirmed via acid value measurements. Additionally, for quality determination, volatile compounds from decorative sugars were measured with an electronic nose. Both applications provide comparable data that provide information about the quality of decorative sugars. [ABSTRACT FROM AUTHOR]

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Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Science & Technology & Economy is the property of Grain Science & Technology & Economy Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the quality monitoring of 18 sunflower oil samples from the EU market, 14 were refined and 4 were cold-pressed. They demonstrated high quality of technological processing with low values of trans-unsaturated fatty acids, acid value, and peroxide value and also met the limits set by legislation in the content of process contaminants 3-monochloropropane-1,2-diol (3-MCPD) esters and glycidyl esters. Measurements of oxidative stability showed a difference in utility value. The average induction period of the oils from the traditional varieties was 2.6 h, predisposing them to cold cooking or short-term frying, while the 11.8 h of the four high oleic sunflower oils (HOSO) indicates the possibility of long-term heat stress. The nutritional benefit is the average vitamin E content of 663 mg/kg oil. The overall sensory quality of the samples was evaluated by a 12-member panel of trained assessors. On the seven-point category scale, the oils were of good to exceptional quality. The cold-pressed oils (CPOs) differed in having, on average, lower trans-unsaturated fatty acid content, process contaminants at unmeasurable levels, and, on average, higher vitamin E concentrations. The specific organoleptic properties of the CPOs were characterized by a pleasant nutty and sunflower seed flavor. [ABSTRACT FROM AUTHOR]

To determine the acid values of tobacco flavors by coulometric titration, the platinum electrode-platinum wire electrode was used as the electrolytic electrode pair, antimony electrode-SCE (saturated calomel electrode) was used as the indicating electrode pair, and 0.5 mol/L potassium chloride solution was used as the electrolyte. The solution was titrated to the pH value of 8.0 by the reaction of electrolytically generated hydroxide ions with free acids in a tobacco flavor sample. Then, the acid value of an experimental tobacco flavor could be calculated by the electrolytic time reached to the titration end point according to Faraday's electrolysis laws, and the spiked recovery experiments were also conducted to validate the method. The results showed that: 1) The recovery range of this method was 96.50%-102.47%, and the relative standard deviations among repeated test results were all less than 1.4%. 2) The acid values of 20 tobacco flavor samples determined by this method showed no significant difference with the potentiometric titration method specified in the tobacco industry standard. 3) The coulometric titration method was suitable for quality control in actual production with convenient operation, less time consuming, and satisfactory precision and accuracy of results. [ABSTRACT FROM AUTHOR]

在芝麻香油精制过程中，自然沉降规律受诸多因素影响，为探索提升芝麻香油精制效率的技术手段，以脱皮和未脱皮芝麻所得芝麻香油为研究对象，通过测定芝麻原油与沉淀物组成，并结合沉降过程中沉淀物含量、磷脂含量、酸值、过氧化值、沉淀物压缩速度的变化规律，考察芝麻脱皮对芝麻香油自然沉降过程的影响。结果表明：相比未脱皮芝麻香油，脱皮芝麻香油在线性沉降阶段的沉降效率高约5百分点；芝麻香油沉淀物的90%以上是粗脂肪，还有少量水分、磷脂、蛋白质、糖形成的胶杂，水和磷脂发生明显聚集；沉淀物的酸值远高于芝麻香油，但过氧化值变化不明显；芝麻香油磷脂含量与沉淀物含量变化呈现相似的趋势，上、下层油中磷脂含量和酸值在线性沉降阶段后差异较小；脱皮芝麻香油沉淀物初始高度远低于未脱皮芝麻香油，且在线性沉降阶段压缩速度快于未脱皮芝麻香油，最终成品油得率高于未脱皮芝麻香油约3百分点。综上，脱皮有利于芝麻香油的自然沉降以及获得更高的得率。In the refining process of fragrant sesame oil, its natural sedimentation pattern is affected by many factors. In order to explore the technique to improve the refining efficiency of fragrant sesame oil, fragrant sesame oil obtained from peeled and unpeeled sesame was used as the research object, the compositions of crude sesame oil and precipitates were measured, and the changes in precipitates content, phospholipids content, acid value, peroxide value, and compression rate of precipitates during the sedimentation process were analyzed to investigate the effect of sesame peeling on the natural sedimentation process of fragrant sesame oil. The results showed that compared with unpeeled sesame oil, the peeled fragrant sesame oil showed a high sedimentation efficiency of about 5 percentages higher in the linear sedimentation stage. More than 90% of precipitates was crude fat, with small amounts of water, phospholipids, proteins, and sugars forming colloidal impurity, with significant aggregation of water and phospholipids. The acid value of the precipitates was much higher than that of the fragrant sesame oil, but the change of peroxide value was not significant. The changes of phospholipids content showed similar trends with precipitates content, and the differences of phospholipids content and acid value in the upper and lower oil were smaller after the linear sedimentation stage. The initial height of the precipitates of peeled fragrant sesame oil was much lower than that of unpeeled fragrant sesame oil, and the compression rate was faster than that of unpeeled fragrant sesame oil during the linear sedimentation stage as well as the final yield was about 3 percentages higher than that of unpeeled fragrant sesame oil. In conclusion, peeling is beneficial for the natural sedimentation of fragrant sesame oil and achieving higher yield.

Acid value (AV) serves as an important indicator to assess the quality of oil, which can be used to judge the deterioration of edible oil. In order to realize the quantitative prediction of the AV of camellia seed oil, which was made from camellia oleifolia, hyperspectral data of 168 camellia seed oil samples were collected using a hyperspectral imaging system, which were related to their AV content measured via classical chemical titration. On the basis of hyperspectral full wavelengths, characteristic wavelengths, and fusing spectral and image features, the quantitative prediction AV models for camellia seed oil were established. The results demonstrating the 2Der-SPA-GLCM-PLSR model fusing spectral and image features stood out as the optimal choices for the AV prediction of camellia seed oil, with the correlation coefficient of calibration set (Rc2) and the correlation coefficient of prediction set (Rp2) at 0.9698 and 0.9581, respectively. Compared with those of 2Der-SPA-PLSR, the Rc2 and Rp2 were improved by 2.11% and 2.57%, respectively. Compared with those of 2Der-PLSR, the Rc2 and Rp2 were improved by 5.02% and 5.31%, respectively. Compared with the model based on original spectrum, the Rc2 and Rp2 were improved by 32.63% and 40.11%, respectively. After spectral preprocessing, characteristic wavelength selection, and fusing spectral and image features, the correlation coefficient of the optimal AV prediction model was continuously improved, while the root mean square error was continuously decreased. The research demonstrated that hyperspectral imaging technology could precisely and quantitatively predict the AV of camellia seed oil and also provide a new environmental method for detecting the AV of other edible oils, which is conducive to sustainable development.

Copyright of Food Science & Technology & Economy is the property of Grain Science & Technology & Economy Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The purpose of this experiment was to study the effect of oryzanol on determination of acid value in forage rice bran oil. Four forage rice bran oil from market or extracted by forage rice bran were selected and content of ooryzanol in oil were determination by HPLC method. Three method, thymol phthalein indicator, Alkali Blue 6B indicator and potentiometric titration, were used to determine acid value in forage rice bran oil. The treatment group were selected edible rice bran oil and forage soybean oil. Then, different quantitative ooryzanol were added to the forage rice bran oil and blank Solvent. The acid value of these oid were determined by thymol phthalein indicato and potentiometric titration individually. The results showed that: ① Alkali Blue 6B indicator was un applicable on determination of acid value in forage rice bran oil. ② The apparent acid value by thymol phthalein indicator titration was the content of oryzanol increased linearly with the content of oryzanol increasing. ③ The content of oryzanol had no significant influence on the acid value by potentiometric titration. ④ Oryzanol would caused a second jump around pH 12 during potential titration. ⑤ The volume of the titrated liquid was significantly linear with the content of oryzanol in both methods. ⑥ Using the solvent with the same content of oryzanol as a blank control, the acid valence determined by thymol phthalein indicator method was no different from the potential titration method. ⑦ The precision of potential titration was higher than that of thymol phthalein indicator. In sum‐ mary, potential titration should be preferred for determination of acid value in forage rice bran oil, and thymol phthalein indicator requires a solvent containing the same content of oryzanol as a blank control. [ABSTRACT FROM AUTHOR]

The object of the study is the analytical values of lipids of milk thistle seeds of a modified composition, namely acid and peroxide values, as well as the induction period of lipids of chocolate mass with the addition of milk thistle seeds. The paper substantiates rational parameters of thistle seed processing for the inactivation of lipases and lipoxygenases. Approximate dependences of the acid and peroxide values of thistle seed lipids on the pH of the wetting solution and the wetting degree of seeds were obtained. This makes it possible to substantiate such rational processing parameters of thistle seeds that inhibit the accumulation of free fatty acids and primary oxidation products in seeds during storage. An increase in the induction period of the oxidation of the lipid component of the chocolate mass with the use of thistle seeds of a modified composition was proven, which is 2.5 times higher than the induction period of the chocolate mass sample with thistle seeds with a native enzyme complex. The research results make it possible to develop a technology of healthy chocolate mass using thistle seeds of a modified composition, the lipid component of such mass is stable to oxidation and hydrolysis. The data obtained in the work are explained by an increase in the ability to inactivate lipolytic and lipoxygenase enzymes of milk thistle at high humidity in an acidic environment under the influence of microwave radiation. The advantage of the obtained results is the possibility of not violating the integrity of thistle seeds during the inactivation of the enzyme complex, which allows extending the shelf life of this raw material. An applied aspect of using the scientific result is the possibility of expanding the range of healthy chocolate masses with the use of thistle seeds. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

为解决国标法测定植物油酸值、过氧化值溶剂安全性问题，以核桃油为实验材料，建立以更安全且容易获取的石油醚、二氯甲烷分别代替GB 5009.229—2016和GB 5009.227—2016中乙醚、三氯甲烷，测定植物油的酸值和过氧化值的方法，考察方法的精密度,采用国标法和所建立方法测定4种植物油的酸值、过氧化值，并对结果进行t检验，考察方法的准确度。结果表明：所建立方法平行测定了6次核桃油的酸值、过氧化值，其相对标准偏差（RSD）分别为2.055%、1.318%；国标法和本实验方法同时测定4种植物油的酸值、过氧化值p值均大于0.05，两种方法不存在显著性差异。所建立的方法精密度和准确度均较好，并且提高了检测安全性，可用于植物油的酸值和过氧化值测定。In order to solve the problem of solvent safety in the determination of acid value and peroxide value of vegetable oil by national standard method, using walnut oil as experimental material, a method was established to determine the acid value and peroxide value of vegetable oil by replacing ethyl ether and trichloromethane in GB 5009.229-2016 and GB 5009.227-2016 with petroleum ether and dichloromethane, which were safer and easily available, respectively. The precision of the method was investigated.The acid values and peroxide values of four vegetable oils were determined by national standard method and the established method, and the results were subjected to t-test to examine the accuracy of the method. The results showed that the acid value and peroxide value of walnut oil were determined 6 times in parallel, the RSD values of the established methods were 2.055% and 1.318%, respectively.The p-values of acid values and peroxide values of the four vegetable oils by national standard method and the established method were all greater than 0.05, showing no significant difference between the two methods. The established method is characterized by better precision and accuracy, and improves assay safety, so it can be used for the determination of acid value and peroxide value of vegetable oil.

Flaxseed consumption has been prioritized by health-conscious people all over the world. Its consumption raises interest to it both from a personal and an industrial prospect due to its remarkable fatty acids profile. Besides its high content of unsaturated fatty acids, flaxseed oil is known for its low omega 6/omega 3 ratio, which may possess health improving properties because this oil is precursor of anti-inflammatory molecules. However, the high amount of polyunsaturated fatty acids in flaxseed oil causes its high sensitivity to high temperatures, to light and to oxygen, which may lead to its oxidation and quality degradation. Screw pressing can produce high quality oil but in lesser volume, which could be disadvantage. Therefore, the extraction process must be optimized for maximizing oil recovery, while maintaining oxidation indicators within limits specified by regulations, as well as a potentially health beneficial fatty acid profile. Optimization of screw press parameters for pressing out the flaxseed oil were investigated by Response Surface Methodology. Both size of the cake outlet and the speed of the screw pressing were optimized, and the values that provided the highest experimental oil recovery, 41.4%, were of 1 mm and 155.89 rpm respectively. Although the overall trend in oil extraction showed a rising oil recovery when screw speeds increased from 98.73 up to 213.05 rpm, certain fluctuations were observed in oil extraction with varying outlet cake sizes. However, there was an inversely-proportional function between the oil recovery and the size of the cake outlet, therefore, screw speed provided a minor, non-significant effect while the size of the cake outlet proved to have a strong effect on oil recovery. The highest acid value and peroxide value accounted to 0.71 mg KOH/g and to 7.71 meq/kg respectively. Sediment content (SC) of screw pressed flax oil ranged between 9.12~14%. During the oil extraction at the maximum yield, temperature increased, however the ratio of omega 6 to omega 3 in the obtained oil still remained low.

摘要：为了对DHA藻油调和油的开发和合理烹饪提供相关指导，将DHA藻油分别按菜籽油质量的2%、3%、5%、10%、15%与菜籽油复配制成菜籽油-DHA藻油调和油，并以蒸、炒、烧三种不同方式烹饪鸡肉，测定烹饪前后油样的脂肪酸组成、酸值和过氧化值的变化，分析探讨DHA藻油比例及烹饪方式对调和油脂肪酸组成及理化指标的影响。结果表明：烹饪后，调和油的单不饱和脂肪酸含量减少，饱和脂肪酸和多不饱和脂肪酸含量增加；三种主要脂肪酸油酸、亚油酸、亚麻酸含量随DHA藻油比例增加呈不规律波动变化；除DHA藻油比例为2%的调和油外，其余调和油的酸值均在烹饪后增加，其中，DHA比例为3%、5%和10%的调和油炒鸡肉后酸值增加最大，蒸和烧这两种烹饪方式对酸值的影响相对较小；纯菜籽油、DHA藻油比例为15%的调和油的过氧化值增加量明显大于其他的调和油，总体上炒较另外两种烹饪方式更易导致过氧化值增加。综上，建议蒸鸡肉或烧鸡肉宜采用DHA藻油比例为2%、3%、5%的调和油，炒鸡肉则不宜采用DHA藻油调和油。 Abstract：To provide relevant guidance for the development and reasonable cooking of edible blended oil of DHA algal oil, DHA algal oil was blended with rapeseed oil at the mass ratios of 2%, 3%, 5%, 10% and 15%, respectively. The blended oil was used to cook chicken with different methods (steaming, stir-frying and boiling). The fatty acid composition, acid value and peroxide value of the blended oil before and after cooking were measured, and the effects of DHA algal oil ratio and cooking methods on fatty acid composition and physical and chemical indexes of blended oil were analyzed and discussed. The results showed that after cooking, the content of MUFA in blended oil decreased, while the contents of SFA and PUFA increased. The contents of three main fatty acids, oleic acid, linoleic acid and linolenic acid, fluctuated irregularly with the increase of DHA algal oil ratio. Except for the blended oil with 2% DHA algal oil, the acid value of the other blended oil increased after cooking. The blended oil with 3%, 5% and 10% DHA algal oil after stir-frying chicken showed the largest increase, and the cooking methods of steaming and boiling had relatively little effect on the acid value. The peroxide value increments of rapeseed oil without DHA and blended oil with 15% DHA algal oil were significantly greater than that of other blended oils, and stir-frying was more likely to lead to an increase in peroxide value than the other two cooking methods. In summary, it is recommended that steaming or boiling chicken should use blended oil with 2%, 3% and 5% DHA algal oil, while stir-frying chicken should not use DHA algal oil blended oil.

为清除合成乳化剂硬脂酰乳酸钠（SSL）对铜皂络合比色技术测定油脂酸价过程的正向干扰，开发了一种固相萃取（SPE）清除SSL的技术。用含2%异丙醇的环己烷为固相萃取流动相和油脂样品溶解液，通过离子排斥色谱检测油脂皂化水解后释放的游离乳酸的含量，间接评估SPE净化处理前后油脂中的SSL含量,并结合铜皂络合比色技术测定的酸价变化，评价所建立的SPE技术对去除油脂中SSL的效果。结果表明：SPE技术可有效去除油脂中的SSL，明显消除油脂中SSL对铜皂络合比色法测定酸价的干扰，不会导致油脂样品脂肪酸含量损失。对于含SSL的食用油脂试样，经SPE技术净化处理后，铜皂络合比色法测定酸价过程的干扰明显降低。To eliminate the positive interference of synthetic emulsifier sodium stearyl lactate (SSL) in the determination of acid value by cupric-pyridine colorimetric method,a solid-phase extraction (SPE) technique for cleaning SSL was developed. Using cyclohexane containing 2% isopropyl alcohol as mobile phase of SPE and oil sample solution, the content of SSL in oils before and after SPE was indirectly evaluated by detecting the content of free lactic acid released after saponification and hydrolysis of oils by ion exclusion chromatography. The effect of the established SPE technique on the removal of SSL from oils was evaluated by combining the acid value change measured by cupric-pyridine colorimetric method.The results showed that the SPE method could effectively remove SSL from oil, and obviously eliminate the interference of SSL on the determination of acid value by cupric-pyridine colorimetric method, without causing the loss of fatty acid content in oil samples.After purification by SPE, the interference of the acid value determination by cupric-pyridine colorimetric method is significantly reduced for the samples containing SSL edible oils.

In order to investigate the deterioration of the quality of low-temperature fried crisp dates during storage, four packaging methods, including PET vacuum packaging, PET vacuum+deoxidiser packaging, aluminium foil vacuum packaging and aluminium foil vacuum+deoxidiser packaging, were used to analyse the changes of acid value and peroxide value at different storage temperatures (25, 35 and 45 ℃) and to establish a prediction model for the shelf life of low-temperature fried crisp dates by combining the Arrhenius formula. The results showed that the acid value and peroxide value of fried crispy dates in the four packaging methods showed an increasing trend at different storage temperatures, with a low rate of change at 25 ℃. In terms of packaging effect, the lowest oxidation rate was observed in the aluminium foil vacuum+deoxidiser packaging method (K value = 0.0131 for acid value kinetic model and K value=0.0147 for peroxide value kinetic model), and the R2 of the predicted shelf-life model was >0.90, with a good fit and the model error of the predicted shelf-life value was less than 10%. By comparing the quality changes of vacuum and low-temperature fried crispy dates in different packaging methods, the best result was obtained with the aluminium foil vacuum+deoxidiser packaging, which increased the acid value by 0.322 mg/g and peroxide value by 0.026 g/100 g for 60 days at room temperature, and the predicted shelf life reached 180 days.

Healthy foods and green processing are currently in the focus of scientific attention. Flax is considered a superfood that includes numerous beneficial ingredients. Its oil is a great source of polyunsaturated fatty acids. However, the heat-sensitive futures of the polyunsaturated fatty acids require low-temperature methods. Screw pressing can produce oils at lower temperatures, but a lower oil capacity makes it less advantageous. Pre-treatment of seeds as a crucial pre-processing stage affects the quality and quantity of oil. This research featured the effect of moisture content in flax seeds on the quantity and quality flax seed oil. The study involved local flax (Linum usitatissimum L.) from the Qashqadaryo Region, Uzbekistan. Standard methods were used to define the quality parameters of oil, i.e., acid value, free fatty acids content, peroxide value, oil recovery, and sediment content. Regression equations were obtained using the method of regression analysis. The highest oil recovery of 40.99% was observed at the moisture content of 9.56%. At 7.55%, the oil recovery dropped by 3.17%. The sediment content in the oil increased at lower moisture contents in the flax seeds (14.62–5.55%). The acid value, peroxide value, and free fatty acid content demonstrated both downward and upward trends when the moisture content increased. The moisture content in flax seeds affected the quality and quantity profile of screw-pressed oil. The optimal parameters of oil processing can yield health-beneficial and highly nutritional oil.

摘要：旨在为提高油莎豆的贮藏稳定性，采用微波对油莎豆进行预处理，研究了冷藏（4 ℃）和常温（20~31 ℃）贮藏条件下油莎豆水分含量、脂肪酶活性及其油脂酸值和过氧化值的变化规律，同时测定了油莎豆油的脂肪酸组成和脂质伴随物含量。结果表明：在常温贮藏或冷藏过程中，油莎豆的水分含量、脂肪酶活性及油莎豆油的酸值、过氧化值均呈一定增长趋势，微波预处理显著降低了油莎豆的水分含量、脂肪酶活性和油莎豆油的酸值；常温贮藏和冷藏120 d后，704 W 处理270 s制备的油莎豆油的酸值（KOH）小于4 mg/100 g，显著低于未经微波预处理的油莎豆油，满足国标（GB 2716—2018）的要求；微波预处理对油莎豆油脂肪酸组成无显著影响，但能提高油莎豆油中生育酚和总酚的含量，其分别在400 W处理270 s、704 W处理210 s时达到最高，为41.70 mg/100 g和10.21 mg/100 g；经微波预处理后，油莎豆油植物甾醇含量总体较空白组有所降低，但保留率在73.05%以上。综上，微波预处理对油莎豆的安全贮藏及其油脂中脂质伴随物的溶出有积极作用。In order to improve the storage stability of tiger nut, the tiger nut was pretreated by microwave and stored at low temperature (4 ℃) and room temperature (20-31 ℃), and the indicators′ change including moisture content and lipase activity of tiger nut, and acid value and peroxide value of its oil were studied. Meanwhile, the fatty acid composition and lipid concomitant content of tiger nut oil were investigated. The results showed that during the storage at room temperature or low temperature, the moisture content, lipase activity of tiger nut and acid value, peroxide value of its oil showed an increasing trend, and microwave pretreatment could significantly reduce the moisture content and lipase activity of tiger nut, and acid value of tiger nut oil. After storage for 120 d at low or room temperature, the acid value of oil from tiger nut treated with the microwave power of 704 W for 270 s was less than 4 mgKOH/100 g, which was significantly lower than the control group, still met the requirements of the national standard (GB 2716-2018). The microwave pretreatment couldn′t affect the fatty acid composition of tiger nut oil, however, rendered the content of tocopherol and total phenol of tiger nut oil to a higher level, reaching their highest at 400 W for 270 s and 704 W for 210 s, respectively, which were 41.70 mg/100 g and 10.21 mg/100 g. After microwave pretreatment, the sterol content of the tiger nut oil was lower than the control group, but the sterol retention rate was above 73.05%. In a word, microwave pretreatment positively impacts the storage safety and the dissolution of lipid concomitant of tiger nut oil.

In Bangladesh, the annual production of rubber seeds is typically left untapped although the seeds contained a high percentage of oil but underutilized without any value-added utilization. This study aims to evaluate the geographical effect on physicochemical properties, fatty acid composition and the antimicrobial activity of oil extracted from rubber seeds. Seeds were collected from three different regions of Bangladesh and the oil was extracted by the soxhlet method using n-hexane as a solvent. Results demonstrated that the geographical regions have some significant effect on the properties of rubber seed oil (RSO). The physicochemical properties of RSO varied from region to region. For example, the percent of yield, higher heating value, and flash point varied from 50.0 to 50.8 %, 31.8–33.3 kJ/g, and 237–245 °C, respectively. The chemical parameters, such as acid value, iodine value, and hydroxyl value varied from 13.3 to 18.2 mg KOH/g, 132–137 g I2/100g, and 47.7–55.8 mg KOH/g, respectively. Chromatographic analysis showed that RSO mainly contains palmitic, linoleic, linolenic, and stearic acid. Regional variations were also seen in the composition of these fatty acids. Most notably, regardless of the rubber seeds collected from various locations, RSO exhibited inhibitory activity against only gram positive bacteria. The zone of inhibition range for different tested gram positive bacteria was 2.33–11.17 mm irrespective of different RSO samples.

Recently, enzymatic method has been used to prepare biodiesel using various oils. But the high acid value of the biodiesel product using enzyme as a catalyst has been one issue. In this work, an attempt to reduce the acid value of fatty acid ethyl ester (FAEE) product to satisfy the specified requirement (AV ≤ 0.5 mgKOH/g), a complex enzyme-catalyzed method was used for the ethanolysis of Semen Abutili seed oil (SASO) (AV = 5.5 ± 0.3 mgKOH/g). The effects of various variables (constituents of complex enzyme, type and addition of water removal agent, time, temperature, enzyme addition load, substrate ratio) on the enzymatic reaction were investigated. The optimal reaction conditions were: 1% addition of liquid lipase Eversa® Transform 2.0% and 0.8% of enzyme dry powder CALB, reaction temperature 35°C, alcohol-oil ratio 9:1 (mol/mol), 0.8 g/g of 4A-MS and reaction time 24 h. Under the optimal reaction conditions, the FAEE yield was 90.8% ± 1.5% and its acid value was decreased from 12.0 ± 0.2 mgKOH/g to 0.39 ± 0.10 mgKOH/g. In further evaluating the feasibility of preparing FAEE from SASO, the FAEE products obtained under the optimal reaction conditions were purified and evaluated with reference to the ASTM D6751 standard for the main physicochemical indexes. The results obtained were in accordance with the requirements except for the oxidative stability.

Polyethylene terephthalate (PET) bottles come in various colours depending on the usage or the manufacturer's branding preference. However, post-consumer PET bottles are known to be non-biodegradable, hence the development of various routes to convert them to other useful products. This work presents the microwave–assisted solvolysis of coloured PET in glycerol media to determine the effect of flake pigmentation on the degree of PET decomposition and the nature of the products. A two-factor, 3 - level Central Composite Design was used in the design of the experiment, with reaction time and NaOH concentration was chosen as the design variables. The results obtained showed that the solvolysis of pigmented PET in glycerol media is dependent on the reaction time and NaOH concentration, but is independent of the flake pigmentation. The acid values of the products, as well as the IR spectroscopy results, indicated that chemically similar products were obtained for any given run, irrespective of the colour of the PET flake used.

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Walnuts (Juglans regia) are characterized by a high fat content of approximately 73%. The oil contained in the nuts is rich in unsaturated fatty acids, including monounsaturated oleic acid and polyunsaturated fatty acids, both of the n-3 and n-6 family. One important thermal process for nuts is roasting, which significantly increases their palatability. Technically, roasting is a drying process at high temperatures. The purpose of roasting is to reveal new flavor and aroma properties of the raw material. The aim of the current study was to determine and compare the fatty acid composition and oxidative and hydrolytic stability of oils extracted from both roasted and raw walnuts. [ABSTRACT FROM AUTHOR]

This article explores the optimization of microwave-assisted extraction (MAE) technology for the extraction of turmeric oil. The study used response surface methodology (RSM) to analyze the effects of process variables on the oil yield and quality. The results indicated that hexane was a more effective solvent compared to petroleum ether, and the optimal conditions for extraction were a microwave power of 300 watts and an extraction time of 20 minutes. The study concludes that MAE is a safe, efficient, and economically feasible method for turmeric oil extraction, with potential applications in various industries and medical science. [Extracted from the article]

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The object of research is organic and inorganic lemon balm. The subject of research is the antioxidant properties of these plants. One of the most problematic areas is that organic products have a slightly different chemical composition, which is due to the lack of fertilizers during their cultivation. The research hypothesis is that organic plants naturally release more phenols and polyphenols, which are needed to fight pests. At the same time, polyphenol compounds have antioxidant properties. The work investigated the total content of polyphenols in organic and inorganic lemon balm. The content of polyphenols in terms of gallic acid was determined by the spectrophotometric method by reaction with the Folin-Chocalteu reagent. In order to determine the antioxidant properties, the content of the peroxide number and the acid number of the fatty base during storage were determined. As a fat base, a mixture of organic butter and organic rye oil was chosen in a ratio of 75:25. Dried lemon balm was added in the amount of 4 % to the mass of fat. Changes in the fat base were determined in three samples: without the addition of lemon balm, with the addition of dried inorganic and organic lemon balm. The samples were stored in a thermostat at a temperature of 50 °C for 10 days. Studies were conducted every 2 days. The amount of peroxides was determined by the iodometric method. The acid number content was determined every 5 days by the titration method. It has been established that organic lemon balm has better antioxidant properties. This is due to the content of polyphenolic substances. So, the content of polyphenols in ordinary lemon balm is 14.1 mg/g, and in organic – 26.5 mg/g. Research has established that the value of the peroxide number after 10 days of storage was 17 ½O for the sample with the addition of organic lemon balm and 22 ½O for the sample with the addition of ordinary lemon balm. The sample without the addition of lemon balm had a value of 25 ½O. The value of acid number of fat on the tenth day of storage was 1.4 for the sample with the addition of inorganic lemon balm and 1.1 for the sample with the addition of organic lemon balm. Further research is planned to be devoted to the effect of plant organic antioxidants on the lipid fraction of food products. [ABSTRACT FROM AUTHOR]

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The rapid detection of lipid oxidation in frozen pork was carried out by using Raman spectroscopy combined with chemometric methods. Frozen pork stored for 0–360 days was selected in this study, and the regression relationship between acid value or peroxide value and storage time was established by the least squares method. Raman spectra were collected with a portable Raman spectrometer and were preprocessed by Savitzky-Golay with five-point smoothing (SG-5), standard normal variate correction (SNV) or adaptive iteratively re-weighted penalized least squares (airPLS). The partial least square regression (PLSR) was used for modeling and analysis. Then competitive adaptive reweighted sampling (CARS) was used to select the Raman characteristic variables for the best preprocessed spectra to establish a CARS-PLSR model. It was found that the correlation between peroxide value and storage time was more significant during the storage period (P = 0.000 3 < 0.05). The prediction models with spectral preprocessing by using SNV and airPLS performed best. The CARS-PLSR model showed improved prediction performance. The CARS-PLSR models for prediction of acid and peroxide values had the following performance parameters: coefficient of determination for calibration (R2c), 0.88 and 0.84; root mean square error of cross-validation (RMSECV), 0.31 and 2.33; coefficient of determination for prediction (R2p), 0.76 and 0.75; root mean square error of prediction (RMSEP), 0.17 and 1.87, and ratio of performance to deviation (RPD), 2.59 and 1.90, respectively. In conclusion, our results show that the peroxide value of frozen pork is significantly correlated with storage time. The degree of lipid oxidation in frozen pork can be rapidly determined by using Raman spectroscopy.

Biodiesel in Indonesia is a mixture of Fatty Acid Methyl Ester (FAME) and diesel oil. Mixing FAME and diesel oil is challenging since FAME is separated from diesel oil at low temperatures. Changes in the physico-chemical properties of biodiesel during storage decrease biodiesel quality due to dissolved oxygen, potentially damaging the engine. Using glycerol ester (GE) as an additive can be an alternative solution to tackle that problem. This research examined the stability of GE-added biodiesel. As a comparison, commercial diethyl ether (DEE) additive was used. The concentration of additive added to biodiesel varied at 1000, 2000, and 3000 ppm while the storage temperature varied at 12, 25, and 42℃. The stability of biodiesel was evaluated for three months by measuring the acid value, viscosity, corrosion rate, and water content. The acid values ​​​​of the various types and concentrations of additives still meet the SNI 7182-2015 standard (0.5 mg KOH g-1 sample) with a value range of 0.148- 0.392 mg KOH g-1 sample. Kinematic viscosity had a value range of 3.12-3.58 cst, which also meets the SNI 7182-2015 standard (2.3-6 cst). The highest corrosion rate for GE and DEE was in the first week, with values of 0.447 and 0.261 mpy, respectively. Both B50 biodiesel control and the addition of 1000 ppm GE had the same water content value on the 18th day, which was 0.046%, and this value was considered the highest water content. This means adding an additive can maintain the water content in B50 biodiesel. Overall, GE additives in B50 biodiesel with various concentrations comply with SNI 7182-2015 standard.

Near infrared spectroscopy was applied to the rapid determination of peroxide value and acid value in rice bran oil. Using chemical titration to determine the content of peroxide value and acid value in rice bran oil as a reference method, using near infrared spectroscopy analysis technology combined with partial least squares regression, established the near infrared quantitative analysis model. The correlation coefficients of the established peroxide value and acid value quantitative analysis models were 99.11% and 99.72%, the standard deviation of prediction were 0.436 7% and 0.044 78%, and the cross validation standard deviation were 0.452 2% and 0.046 69%. The calibration model was independently verified externally with 78 samples. The absolute errors of peroxide value and acid value were –0.78%~0.82% and –0.142%~0.139%. The relative errors of peroxide value and acid value were –13.21%~14.44% and –14.85%~12.46%. The established quantitative analysis model and method is simple, rapid and accurate in the content determination of peroxide value and acid value in rice bran oil.

Palm oil has a bad reputation due to the exploitation of farmers and the destruction of endangered animal habitats. Therefore, many consumers wish to avoid the use of palm oil. Decorative sugar contains a small amount of palm oil to prevent the sugar from melting on hot bakery products. High-oleic sunflower oil used as a substitute for palm oil was analyzed in this study via multispectral imaging and an electronic nose, two methods suitable for potential large-batch analysis of sugar/oil coatings. Multispectral imaging is a nondestructive method for comparing the wavelength reflections of the surface of a sample. Reference samples enabled the estimation of the quality of unknown samples, which were confirmed via acid value measurements. Additionally, for quality determination, volatile compounds from decorative sugars were measured with an electronic nose. Both applications provide comparable data that provide information about the quality of decorative sugars.

In the quality monitoring of 18 sunflower oil samples from the EU market, 14 were refined and 4 were cold-pressed. They demonstrated high quality of technological processing with low values of trans-unsaturated fatty acids, acid value, and peroxide value and also met the limits set by legislation in the content of process contaminants 3-monochloropropane-1,2-diol (3-MCPD) esters and glycidyl esters. Measurements of oxidative stability showed a difference in utility value. The average induction period of the oils from the traditional varieties was 2.6 h, predisposing them to cold cooking or short-term frying, while the 11.8 h of the four high oleic sunflower oils (HOSO) indicates the possibility of long-term heat stress. The nutritional benefit is the average vitamin E content of 663 mg/kg oil. The overall sensory quality of the samples was evaluated by a 12-member panel of trained assessors. On the seven-point category scale, the oils were of good to exceptional quality. The cold-pressed oils (CPOs) differed in having, on average, lower trans-unsaturated fatty acid content, process contaminants at unmeasurable levels, and, on average, higher vitamin E concentrations. The specific organoleptic properties of the CPOs were characterized by a pleasant nutty and sunflower seed flavor.

Olives and its oil are considered an imperative element of diet due to their excellent nutritional quality. Geographical factors (i.e., geology, slope, elevation and temperature) and genetic variability in different olive cultivars influence plant growth, yield, oil and profiling of fatty acids. The prime objective of this investigation was to demonstrate the prodigious consequences of high temperature on the growth, production, and fatty acid composition of four olive cultivars (Coratina, Frantoio, Ottobratica and Leccino) at three different geographical locations (BARI, IOF, HRS) with the range of 460-751 m altitude during the year 2017 and 2018. The study has been carried out to investigate different parameters such as climatic conditions (rainfall and temperature), phenological attribute and yield traits (fruit set, fruit weight, yield, and oil content), and oil quality and profiling of fatty acids (free fatty acid contents, peroxide, palmitic acid, palmitoleic acid, oleic acid, linoleic acid, and linolenic acid). The results indicated a positive correlation of yield with rainfall and negative with the temperature was observed among olive cultivars. The results showed higher rainfall (1189 mm) and temperature (37.51 °C) at location-1 and lower rainfall (525 mm) and temperature (36.05 °C) at location-3. Coratina and Frantoio depicted significantly higher fruit set and yield in warmer climatic regions (Location-1 and Location-2) while Leccino and Ottobratica showed better results in the cooler region. Higher oil content was found in Frantoio and Coratina at location-3 among other locations and other cultivars. Overall, the lowest free fatty acid value was exhibited in Coratina and the highest in Ottobratica at all locations in both seasons. The contents of peroxide were observed higher in Leccino and lower in Coratina at all locations. The results revealed less variation among fatty acid composition in cultivars and seasons, however, palmitic acid, palmitoleic acid and oleic acid contents were found higher at location-2, linoleic acid at location-3, and linolenic acid at location-2 in all four olive cultivars. Custer analysis revealed two main groups and group-I contained two subgroups (A and B) while group-II contained three subgroups (C, D and E). In principal component analysis (PCA), PC1 axis had Leccino-L3, Leccino-L1, Frantoio-L1, Ottobratica-L1, Coratina-L1, and Leccino-L3 and explained 91.99% of the total variation. Therefore, geographic location influence growth, yield and olive oil quality attributes. [ABSTRACT FROM AUTHOR]

Puffed grains made from whole wheat, corn or rice grains are ready-to-eat breakfast cereals that do not require additional preparation. Two recipes for puffed grain coatings were developed in the previous studies. Sunflower oil was used in the coating, which may affect storage stability. Due to lipid hydrolysis, free fatty acids may be released, causing rancid off-flavour. The aim of this study was to determine the changes in the acid value of lipids and sensory attributes of sweet-coated puffed wheat grains ‘Badyrak vanilla’ (BV) and ‘Badyrak with whey’ (MC) depending on temperature during their eight-month storage. The products were packaged in metallised polypropylene pouches, 30 g each. The acid value was studied monthly at different storage temperatures (20 ± 2 °С and 4 ± 2 °С). In puffed wheat grain products, 65% of fatty acids are polyunsaturated, 25% monounsaturated, and 10% saturated. The high proportion of unsaturated fatty acids over saturated makes oil more susceptible to oxidation. Literature studies and sensory evaluation of puffed wheat grains allowed setting a limiting acid value at 4.0 mg KOH g−1 lipids. The increase in acid value was storage temperature dependent. Thus, the acid value exceeded the established limit in the fifth month for MC and the sixth month for BV when stored at 20 ± 2 °С. At the same time, noticeable changes in puffed wheat grain flavour were observed. The temperature coefficient (Q10) for MC was 2.0, whereas for BV it was 1.5, indicating that the acid value increase in MC was more affected by temperature than that in BV. [ABSTRACT FROM AUTHOR]

In this study, reused sunflower cooking oil was investigated for rancidity. Three student cafeterias at the University of Dodoma (UDOM) were used for this particular study. Oil samples were analyzed at the University of Dodoma laboratories. Results showed that all parameters were beyond permissible limits by WHO/FAO standards. Acid values ranged between 0.841 and 4.319 mg KOH/g oil, which is beyond the allowable limits by WHO/FAO (0.6 mg KOH/g oil). Peroxide values were found to be 19.5 mill eq O2/kg oil (minimum), and 62 mill eq O2/kg oil (maximum), which are both above the recommended limits by WHO/FAO (10 mill eq O2/kg oil). Iodine values were found to be from 102.87 to 48.26‐g I2/100 g oil, and were all beyond the recommended limits by WHO/FAO, of between 118‐ and 141‐g I2/100 g oil. The study has further revealed that the number of customers that are saved by the three cafeterias exceeds the capacity of the cafeterias. This study also found out that many students (almost 74%) are not aware on general knowledge about rancidity, including health effects of using rancid oils. It is therefore recommended to the national regulatory authorities to formulate strict regulations to guide and control oil rancidity. [ABSTRACT FROM AUTHOR]

Kajmak is a very popular dairy product in Balkan countries, however, it is often a subject of adulteration. The aim of this study was to investigate the effects of kajmak adulteration on its yield and composition, and determine the possibility of detecting the adulteration using the iodine and acid values and sensory evaluation of kajmak quality. In this study, experimental kajmak samples were produced from milk with increased fat contents (by 18 % and 36 %), via the addition of refined palm oil, pig fat and margarine to milk. The experimental kajmak samples had increased yield (21-32 %), changed composition and sensory quality. The control had the lowest iodine value (35.60), while the experimental kajmak with pig fat had the highest value of this constant (49.95), so the chemical constant - iodine value can be useful for detecting of adulterated milk fat in kajmak with refined palm oil, pig fat and margarine. However, these adulterants did not lead to a significant change in the acid value of the kajmak samples. The adulterants - refined palm oil and margarine in experimental kajmak samples could not be detected by sensory analysis.

In order to explore the quality changes of grass carp visceral fish oil under different storage temperatures, the grass carp visceral fish oil was extracted by enzymatic method. The visceral fish oil of grass carp was stored at cold storage (4 ℃), normal temperature (25 ℃) and 37 ℃ for 60 days at constant temperature, and its acid value and peroxide value were determined regularly. Fingerprint characteristic analysis, principal component analysis (PCA) and linear discriminant analysis (LDA) and load analysis and other electronic nose technologies regularly were used to analyze the changes of volatile components. The results showed that the changes of acid value, peroxide value and volatile odor components of grass carp viscera were not obvious during storage at low temperature (4 ℃); The acid value and peroxide value of grass carp visceral crude oil increased significantly at room temperature (25 ℃) and 37 ℃, and the volatile odor components changed significantly, especially at 37 ℃; Taking the acid value and peroxide value as the criteria for judging whether the fish oil was deteriorated, the shelf life was about 55 days at 4 ℃, 40 days at 25 ℃ and 30 days at 37 ℃; The volatile components of fish oil during storage were mainly nitrogen oxides, sulfides and aromatic components. This study provides a theoretical basis for the effective utilization of grass carp viscera.