南瓜籽中油脂含量丰富，是优质的油料资源，从中提取得到的南瓜籽油香味独特，营养价值高，可用于烹饪，还可作为保健食品。新疆的南瓜籽资源丰富，但其加工利用率低，增值有限，且目前南瓜籽油加工技术落后，处于初级阶段。为此，本研究针对目前南瓜籽油制取技术存在的问题，利用绿色、安全的水酶法提取南瓜籽油，确定南瓜籽油的最佳提取条件，分析对比南瓜籽油的品质和挥发性物质，评估南瓜籽油的货架期。主要研究内容和结果如下：

1.水酶法提取南瓜籽油的研究。以裸仁南瓜籽为原料，在80 ℃下烘烤30 min，粉碎后过40目筛，通过单因素和响应面优化试验，确定了水酶法提取南瓜籽油的最优条件：将南瓜籽粉与水按1：6混合，调节pH为6，将中性蛋白酶与纤维素酶1：1复配，添加量2300 U/g，在50 ℃下酶解3 h，南瓜籽油的提取率可达63.61%。

2.超声波辅助水酶法提取南瓜籽油的研究。在水酶法基础上，辅以超声波技术，通过单因素和响应面优化试验，确定超声辅助水酶法提取南瓜籽油的最优条件：超声处理温度40 ℃、超声功率300 W、超声处理时间8 min，南瓜籽油的提油率可达72.23%，比水酶法提高了8.62%。

3.南瓜籽油的品质评价。

对水提法、水酶法、超声波辅助水酶法及压榨法四种不同工艺所提南瓜籽油进行品质评价。

（1）理化指标检测。发现超声波辅助水酶法得到的油脂碘值最高，达129 g/100g；压榨法制取南瓜籽油的酸价和过氧化值均最高，分别为1.7mg/g、2.4 mmol/kg。四种方法提取油脂的理化指标均符合国家标准。

（2）脂肪酸组成检测。发现超声波辅助水酶法所提南瓜籽油的脂肪酸组成与水酶法差别不大，且二者饱和脂肪酸质量分数为（16.92±0.08）%，主要为棕榈酸和硬脂酸；单不饱和脂肪酸质量分数为（29.79±0.11）%，主要为油酸；多不饱和脂肪酸质量分数为（52.80±0.21）%，主要以亚油酸和亚麻酸为主。

（3）生育酚及植物甾醇的含量的测定。在超声辅助法提取南瓜籽油中的总甾醇含量、α-生育酚和γ-生育酚含量最高，分别为202 mg/100g和3.62 mg/100g 、75.4 mg/100g，水酶法提取南瓜籽油的δ-生育酚含量最高，为1.34 mg/100g。水提法样品组中甾醇和生育酚含量均最低。      

（4）挥发性成分分析，水提法、水酶法、超声波辅助水酶法和压榨法制取的南瓜籽油中共检测出95种挥发性物质，主要包括醛类、烃类、酮类和杂环类。不同提取方法得到的南瓜籽油，挥发性物质数量不同，以压榨法最多，达74种，对照组和水酶法居中，分别为65种和63种，超声波辅助水酶法最少，有60种。并利用ROAV值确定了四种南瓜籽油的主体挥发性成分。

（5）将超声波辅助水酶法制取的南瓜籽油与市售葵花籽油、花生油、胡麻籽油、红花籽油进行挥发性成分分析，共检测出120种挥发性物质，主要包括醛类、酮类、烃类、醇类、萜烯类等。不同品种植物油，挥发性物质数量不同，胡麻籽油和南瓜籽油最多，均为60种，其次为花生油和红花籽油，分别为58种和40种，葵花籽油最少，仅有35种。通过聚类热图分析，发现挥发性物质可作为区分不同种类植物油的判别方式。

4.南瓜籽油的货架期研究。以过氧化值为指标，采用Arrehenius方程建立南瓜籽油的货架期模型，得出南瓜籽油在25 ℃条件下密封、避光储藏的货架期预测值为68 d。添加0.02%的抗氧化剂TBHQ，将南瓜籽油的货架期延长至84 d，说明添加抗氧化剂可以有效延长南瓜籽油的货架期。

Pumpkin seed is rich in oil and is a high-quality oil resource. The pumpkin seed oil extracted from pumpkin seed has unique flavor and high nutritional value. It can be used for cooking and health food. Xinjiang is rich in pumpkin seed resources, but its processing and utilization rate is low and its value-added is limited. At present, the processing technology of pumpkin seed oil is backward and in the primary stage. Therefore, aiming at the problems existing in the current pumpkin seed oil preparation technology, this study uses the green and safe water enzyme method to extract pumpkin seed oil, determines the best extraction conditions of pumpkin seed oil, analyzes and compares the quality and volatile substances of pumpkin seed oil, and evaluates the shelf life of pumpkin seed oil. The main research contents and results are as follows:

1. Study on water enzymatic extraction of pumpkin seed oil. Using naked kernel pumpkin seed as raw material, it was baked at 80 ℃ for 30 minutes, crushed and sieved through 40 mesh. Through single factor and response surface optimization test, the optimal conditions for aqueous enzymatic extraction of pumpkin seed oil were determined: pumpkin seed powder was mixed with water at 1:6, pH was adjusted to 6, neutral protease and cellulase were mixed at 1:1, the addition amount was 2300 U/g, and enzymatic hydrolysis at 50 ℃ for 3 hours, the extraction rate of pumpkin seed oil could reach 63.61%.

2. Study on ultrasonic assisted aqueous enzymatic extraction of pumpkin seed oil. On the basis of aqueous enzymatic method, supplemented by ultrasonic technology, through single factor and response surface optimization test, the optimal conditions for ultrasonic assisted aqueous enzymatic method to extract pumpkin seed oil were determined: ultrasonic treatment temperature 40 ℃, ultrasonic power 300 W and ultrasonic treatment time 8 min. the oil extraction rate of pumpkin seed oil was 72.23%, which was 8.62% higher than that of aqueous enzymatic method.

3. Quality evaluation of pumpkin seed oil.

The quality of pumpkin seed oil extracted by water extraction, water enzyme method, ultrasonic assisted water enzyme method and pressing method was evaluated.

(1) The results of physical and chemical indexes showed that the iodine value of oil obtained by ultrasonic assisted hydroenzymatic method was the highest, up to 129 g/100g; The acid value and peroxide value of pumpkin seed oil obtained by pressing method were the highest, which were 1.7mg/g and 2.4 mmol/kg respectively. The physicochemical indexes of oil extracted by the four methods meet the national standards.

(2) The fatty acid composition of pumpkin seed oil extracted by ultrasonic assisted hydroenzymatic method was not different from that of hydroenzymatic method, and the mass fraction of saturated fatty acid was (16.92 ± 0.08)%, mainly palmitic acid and stearic acid; The mass fraction of monounsaturated fatty acid was (29.79 ± 0.11)%, mainly oleic acid; The mass fraction of polyunsaturated fatty acids was (52.80 ± 0.21)%, mainly linoleic acid and linolenic acid.

(3) Determination of tocopherol and phytosterol. Extraction of pumpkin seed oil by ultrasonic assisted method it's total sterol content、α- Tocopherol and γ- Tocopherol content was the highest, 202 mg/100g, 3.62 mg/100g and 75.4 mg/100g, extraction of pumpkin seed oil by aqueous enzymatic method respectively δ- Tocopherol content was the highest, 1.34 mg/100g. The contents of sterol and tocopherol in the water extraction sample group were the lowest.

(4) Analysis of volatile components. A total of 95 volatile substances were detected in pumpkin seed oil prepared by water extraction, water enzyme method, ultrasonic assisted water enzyme method and pressing method, mainly including aldehydes, hydrocarbons, ketones and heterocycles. The amount of volatile substances in pumpkin seed oil obtained by different extraction methods is different. The pressing method is the most, up to 74 species, the control group and water enzyme method are in the middle, 65 species and 63 species respectively, and the ultrasonic assisted water enzyme method is the least, with 60 species. The main volatile components of four pumpkin seed oils were determined by roav value.

(5) The volatile components of pumpkin seed oil prepared by ultrasonic assisted hydroenzymatic method and commercial sunflower seed oil, peanut oil, flax seed oil and safflower seed oil were analyzed. A total of 120 volatile substances were detected, mainly including aldehydes, ketones, hydrocarbons, alcohols and terpenes. Different varieties of vegetable oils have different amounts of volatile substances. Flax seed oil and pumpkin seed oil are the most, with 60 species, followed by peanut oil and safflower seed oil, with 58 and 40 species respectively, and sunflower seed oil is the least, with only 35 species. Through cluster heat map analysis, it is found that volatile substances can be used as a way to distinguish different kinds of vegetable oils.

4. Study on shelf life of pumpkin seed oil. Taking the peroxide value as the index, the shelf-life model of pumpkin seed oil was established by Arrehenius equation. The predicted shelf-life of pumpkin seed oil sealed and stored away from light at 25 ℃ was 68 days. Adding 0.02% antioxidant TBHQ extended the shelf life of pumpkin seed oil to 84 days, indicating that adding antioxidants can effectively prolong the shelf life of pumpkin seed oil.