Nutritional Effect Of Carya Nut Kernel On Metabolic Syndrome And Changes Of Functional Components During Traditional Stir-frying Process

Carya Nut, belong to the Juglandaceae family, which is distributed in eastern North America and southeast of Asia with18species and3varieties. There are5species original distributed in China namely C. tonkinensis, C. kweichowensis, C. dabieshanensis, C. cathayensis and C. hunanensis, in addition to C. illinoensis, which is the introduced cultivated species from North America. Because of its high levels of unsaturated fatty acids, tocopherols and phytosterols, tradtitonal Chinese medicine considered Carya nut kernels could tonify "qi" and blood, warm lung and cure cough. Therefore, the Carya nut kernels usually be made in different stir-fried tastes Carya nut, like spiced taste, cream taste and so on. However, current studies were lacked of systematic analysis on nutritional composition of different Carya nut kernel. It also lacked of the influence on nutritional components at different stir-frying processes. In addition, it lacked of modern medicine in exploring health function of Carya nut kernels depth.This study aimed to determine the nutritional and chemical compositions of six Carya species commonly planted in China. In addition, we also studied the antioxidant compounds of water-soluble part and oil-soluble part of C. cathayensis and its antioxidant capacities. At last, we studied the chemical compositions and the physiological effects on improving metabolic syndrome of Carya cathayensis and Carya illinoensis.1. The proximate compositions and the profile of amino acids, minerals, fatty acids, tocopherols and phytosterols were evaluated in six different Carya nut kernels grown in China. The results were showed as flows:lipid (548-728g/kg), protein (78-257g/kg), total ash (15-48g/kg), dietary fiber (80-246g/kg), avaliable carbohydrate protein (19-105g/kg) varied considerably in different Carya nut kernels. Carya nut kernels contained all18amino acids and8essential amino acids. P, K, Mg and Ca were the highest four elements in Carya nut kernels. Carya nut kernels also had high levels of unsaturated fatty acids (beyond90%), and the oleic acid and linoleic acid had significant in different Carya nut kernels. The tocopherol contents ranged from242.4μg/g to581.7μg/g, and y-tocopherol was the main existence. The phytosterol contents ranged from0.85mg/g to1.32mg/g, and β-sitosterol was the main existence. C. dabieshanensis kernel had the highest content of protein, amino acids, unsaturated fatty acids and phytosterols. C. tonkinensis kernel had the highest content of tocopherols. These results suggested that Carya species grown in China can be regarded as a good nut resource for humans.2. The effect of stir-frying Carya cathayensis kernels at varying temperatures (200℃,250℃,300℃,350℃,400℃) and time periods (10min,20min,30min) on total phenolic contents (TPC), phenolic acids, tocopherols, phytosterols and antioxidant capacity was investigated. The concentrations of TPC, phenolic acids, tocopherols and phytosterols in raw C. cathayensis kernels were19.4mg gallic acid equivalent/g dry weight,3.67mg/g,79.5μg/g and1.00mg/g, respectively. The antioxidant from the water and the oil-soluble part of C. cathayensis kernels were78.3mg Trolox equivalent/g dry weight (DPPH radical-scavenging activity) and0.03mg meq/kg (Peroxide value), respectively. Stir-frying at a low temperature over a short time period led to an apparent increase of the studied compounds and antioxidant capacity. However, these values decreased with heating time and temperature increased. In conclusion, it is benefit for stir-frying at a suitable temperature and over a suitable time period during the processing of C. cathayensis.3. We studied the effects on improving metabolic syndrome of Carya cathayensis kernels and Carya illinoensis kernels through high fat. Sprague-Dawley rats (model group) were fed with high-fat feeds and fructose water causing metabolic syndrome. High-fat high-fructose diet rats had the symptoms of insulin resistance, hypertension, impaired glucose tolerance, and dyslipidemia. The Carya cathayensis kernels and Carya illinoensis kernels can reduce glucose, insulin resistance, triglyceride, cholesterol, LDL-C, CRP, IL-6, ALT, AST, ALP, LDH, whereas HDL-C and TNF-a were increased. Carya kernel reduced the risk factors of metabolic syndrome. It is potential to adjuvant treatment in metabolic syndrome. And the Carya illinoensis kernels had better effect on improving metabolic syndrome compared with Carya cathayensis kernels.