HS-SPME GC–MS characterization of volatiles in processed walnuts and their oxidative stability

• Published in: Journal of food science and technology Vol. 57; no. 7; pp. 2693 - 2704
• Main Authors: Hao, Jing, Xu, Xiao-Lin, Jin, Feng, Regenstein, Joe M., Wang, Feng-Jun
• Format: Journal Article
• Language: English
• Published: New Delhi Springer India 01.07.2020; Springer Nature B.V
• Subjects: air drying; Aluminum; aluminum foil; Antioxidants; Cheese; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Edible oils; Food Science; Free radicals; Gas chromatography; Headspace; Malondialdehyde; Mass spectrometry; Mass spectroscopy; Metal foils; Nutrition; oils; Original; Original Article; Oxidation; oxidative stability; Phenols; Scavenging; Shelf life; Solid phase methods; solid phase microextraction; Solid phases; Stability; storage time; Vacuum; Volatiles; Walnuts; Shelf life; Odor volatiles; L; Vacuum package; Processed walnuts
• ISSN: 0022-1155; 0975-8402
• DOI: 10.1007/s13197-020-04305-9

Processed walnuts including hot air-dried and roasted walnuts were prepared. Volatiles in raw and processed walnuts were analyzed using head-space solid phase microextraction combined with gas chromatography and mass spectrometry. Oxidative stability of hot air-dried walnuts in different antioxidants, with or without vacuum package was studied to find a proper package for oxidation stability of hot air-dried walnuts. The results showed that there were 14 volatiles in raw walnuts, 28 in hot air-dried walnuts and 38 in roasted walnuts. The changes of oil quality indices, total phenols, malondialdehyde and free radical scavenging activities during storage at 60 °C showed that the oil oxidation increased with storage time. The addition of antioxidants and vacuum package could slow down the oxidation. Vacuum aluminum foil package (14 × 20 cm) can delay the oil oxidation and extend the shelf life to ~ 230 days of hot air-dried walnuts at 20 °C. With added antioxidant this was extended to ~ 257 days.