No abstract

Pulsed electric fields (PEF) accounts for one of the novel non‐thermal processing and preservation technologies and is regarded as an emerging application with the advantage of minimising the loss of valued bioactive compounds in food processing. In this study, various PEF pulses were applied to jujube pulp before fermentation. The fermentation kinetics, compositions, volatile and sensory characteristics were investigated and compared. Results showed that the PEF pretreatment with ten exponential wave pulses at 1.5 kV cm−1, 1 Hz improved phenolic compounds extraction, especially for caffeic acid, morin and p‐hydroxybenzoic acid. Besides, fifty pulses pretreatment enhanced 10% of the wine dry extract. In addition, PEF pretreatment significantly enriched the floral and fruity volatile notes to jujube wine with a decrease in fusel oil. Consequently, PEF preprocessing is a promising method that can be adopted in winemaking industry to promote wine quality and sensory profile.

No abstract

Characteristic aroma substances of cis‐rose oxide imparts the odorant of “lychee‐like,” while of citronellol is the precursor of it in lychee. The characterization of volatiles of lychee wine fermentation using headspace solid‐phase microextraction gas chromatography‐mass spectrometry combined with headspace gas chromatography‐ion mobility spectrometry were done to regulate processing. Results indicated that the total of 97 volatiles (38 in common) were observed during fermentation, including 39 terpenoids, 5 alcohols, 22 esters, 4 acids, 7 alkenes, 4 ketones and ethers, 3 sulfur compounds and others. Losses of characteristic aromas mainly occurred during primary fermentation more than threefold decrease. The volatility of cis‐rose oxide was stronger than citronellol, which implied that more gentle processing should be performed to protect lychee flavor. Cis‐rose oxide was a mixture of monomer and dimer with unequal proportion, while citronellol was a monomer in lychee. The work provides important new information on aroma development during fermentation. Practical applications Fruit consumption, among which tropical fruit‐based products have gained huge popularity in the recent years. The main high value‐added processed products of lychee pulp are lychee wine and vinegar; however, the typical aroma always decreased or disappeared during fermentation. Therefore, this study aims at providing more information for product improvement and process development.