{"title":"Impact of steaming and roasting heat-treatment on physico-chemical and functional properties of walnut kernel","authors":"Xiaoyan Zhao, Xiangrui Ren, Hongkai Liu, Xiaowei Zhang, Meng Wang, Haifang Hu","doi":"10.1002/aocs.12755","DOIUrl":null,"url":null,"abstract":"<p>In this study, the effect of steaming and roasting treatment on the physicochemical and functional properties of walnut kernel at 95°C for different time (15, 20, and 30 min) was investigated. Steaming and roasting treatments significantly increased the enthalpy change for protein denaturation, in-vitro digestibility, viscosity, storage modulus (<i>G</i>′) and loss modulus (<i>G</i>″) (<i>p</i> < 0.05), the order from high to low was steaming (7.11–8.69 J g<sup>−1</sup>; the gastric and intestinal digestion: 1.21%–17.83% and 1.51%–27.31%, respectively; 134.04–450.49 Pa s; 214.28–1047.14 and 61.72–196.09 Pa) > roasting (6.24–7.07 J g<sup>−1</sup>; the gastric and intestinal digestion: 1.26–15.42% and 1.21–22.37% a, respectively; 16.92–86.07 Pa s; 6.58–209.85 and 3.08–67.14) > untreated (4.53 J g<sup>−1</sup>; the gastric and intestinal digestion: 0.24%–4.18% and 1.00–7.58%, respectively; 17.06 Pa s; 5.78 and 1.79 Pa). All samples contained the essential amino acids, the amino acid score of samples by steaming was the highest. In addition, the protein of walnut kernel after heating treatment contained more α-helix and random coil structures compared to the untreated sample, while β-sheet and β-turns structures decreased. Moreover, the thermal treatment could cause the changes of the water/oil holding capacity, foaming and emulsifying properties of walnut kernel flour. When there were differences between the results of steaming and roasting samples, it was concluded that the water played an important role in steaming. These results suggested that the thermal treatment as an effective approach could improve the physico-chemical, structural and functional properties of walnut kernel and be potentially applied in the food processing.</p>","PeriodicalId":17182,"journal":{"name":"Journal of the American Oil Chemists Society","volume":null,"pages":null},"PeriodicalIF":1.9000,"publicationDate":"2023-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of the American Oil Chemists Society","FirstCategoryId":"97","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/aocs.12755","RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, APPLIED","Score":null,"Total":0}
引用次数: 0
Abstract
In this study, the effect of steaming and roasting treatment on the physicochemical and functional properties of walnut kernel at 95°C for different time (15, 20, and 30 min) was investigated. Steaming and roasting treatments significantly increased the enthalpy change for protein denaturation, in-vitro digestibility, viscosity, storage modulus (G′) and loss modulus (G″) (p < 0.05), the order from high to low was steaming (7.11–8.69 J g−1; the gastric and intestinal digestion: 1.21%–17.83% and 1.51%–27.31%, respectively; 134.04–450.49 Pa s; 214.28–1047.14 and 61.72–196.09 Pa) > roasting (6.24–7.07 J g−1; the gastric and intestinal digestion: 1.26–15.42% and 1.21–22.37% a, respectively; 16.92–86.07 Pa s; 6.58–209.85 and 3.08–67.14) > untreated (4.53 J g−1; the gastric and intestinal digestion: 0.24%–4.18% and 1.00–7.58%, respectively; 17.06 Pa s; 5.78 and 1.79 Pa). All samples contained the essential amino acids, the amino acid score of samples by steaming was the highest. In addition, the protein of walnut kernel after heating treatment contained more α-helix and random coil structures compared to the untreated sample, while β-sheet and β-turns structures decreased. Moreover, the thermal treatment could cause the changes of the water/oil holding capacity, foaming and emulsifying properties of walnut kernel flour. When there were differences between the results of steaming and roasting samples, it was concluded that the water played an important role in steaming. These results suggested that the thermal treatment as an effective approach could improve the physico-chemical, structural and functional properties of walnut kernel and be potentially applied in the food processing.
期刊介绍:
The Journal of the American Oil Chemists’ Society (JAOCS) is an international peer-reviewed journal that publishes significant original scientific research and technological advances on fats, oils, oilseed proteins, and related materials through original research articles, invited reviews, short communications, and letters to the editor. We seek to publish reports that will significantly advance scientific understanding through hypothesis driven research, innovations, and important new information pertaining to analysis, properties, processing, products, and applications of these food and industrial resources. Breakthroughs in food science and technology, biotechnology (including genomics, biomechanisms, biocatalysis and bioprocessing), and industrial products and applications are particularly appropriate.
JAOCS also considers reports on the lipid composition of new, unique, and traditional sources of lipids that definitively address a research hypothesis and advances scientific understanding. However, the genus and species of the source must be verified by appropriate means of classification. In addition, the GPS location of the harvested materials and seed or vegetative samples should be deposited in an accredited germplasm repository. Compositional data suitable for Original Research Articles must embody replicated estimate of tissue constituents, such as oil, protein, carbohydrate, fatty acid, phospholipid, tocopherol, sterol, and carotenoid compositions. Other components unique to the specific plant or animal source may be reported. Furthermore, lipid composition papers should incorporate elements of yeartoyear, environmental, and/ or cultivar variations through use of appropriate statistical analyses.