Differences in Key Storage Qualities and Flavours of Several Different Baked Hazelnuts

Abstract

To scientifically evaluate the storage quality and flavour differences of different baked hazelnuts, this study examined raw hazelnuts (Raw Hazelnuts, RH), traditional baked hazelnuts (Baked hazelnuts, BH), and herbal salt-pepper flavoured hazelnuts (Flavoured hazelnuts, FH). The Schaal oven method was employed to store these samples at 60°C for 18 days, measuring colour, texture and oil oxidation every 3 days. Taste characteristics and volatile flavour compounds were analysed using an electronic tongue and headspace solid phase microextraction/gas chromatography–mass spectrometry (HS-SPME/GC–MS). Results indicated that the FH group maintained superior colour and texture during storage while significantly inhibiting increases in acid value, peroxide value and anisidine value (p < 0.05), thus delaying iodine value decline (p < 0.05). Additionally, electronic tongue analysis revealed a significant increase in salty signals for the FH group alongside notable decreases in astringent, bitter and aftertaste signals (p < 0.05). GC–MS identified a total of 113 volatile compounds; notably, the FH group exhibited the highest diversity with 91 compounds totaling 22,241.14 μg/kg. Based on the OAV value and VIP value, 19 key differential aroma substances were further identified, including 6 ketones, 5 pyrazines, 4 aldehydes, 3 alcohols and 1 ester. 3-nonen-2-one, 4-hexen-3-one and methyl salicylate are unique key aroma compounds in FH samples. This study not only lays a theoretical foundation for the development of new multi-flavour baked hazelnut products, but also provides practical guidance for the application of natural antioxidants in extending the shelf life of nut foods.