title: Volatile organic compounds profile during milk fermentation by Lactobacillus pentosus and correlations between volatiles flavor and carbohydrate metabolism.
abstract: Flavor, as one of the most important properties determining the acceptability and preference of fermented milks, is influenced by compositional and processing factors. In this study, we focused on the volatile organic compounds related to flavor during milk fermentation by Lactobacillus pentosus according to electronic nose analysis. Xylose (1% addition) metabolized by Lb. pentosus strongly affects the flavor of yogurt, with the potent volatile organic compounds of ethanol (3.08%), 2,3-butanedione (7.77%), and acetic acid (22.70%) detected using solid-phase microextraction coupled with gas chromatography-mass spectrometry analysis. Sensoryanalysis also showed skimmed yogurt fermented by Lb. pentosus with 1% xylose had the unique scores of sourness (acetic acid) and butter flavor (2,3-butanedione). Furthermore, α-acetolactate synthase and α-acetolactate decarboxylase in carbohydrate metabolism play important roles in milk fermentation. Under preferable conditions (pH 5.5, 42 °C) for α-acetolactate synthase and α-acetolactate decarboxylase, the relative content of potent flavor compound 2,3-butanedione was 10.13%, which was 2.55% higher than common culture condition (pH 4.5, 37 °C), revealing that xylose metabolized by Lb. pentosus has potential values for the milk product industry, such as the acceptability and preference of fermented milk product.
authors.affiliation: Food Science and Technology Department of the Marine Science School, Ningbo University, Ningbo 315211, P. R. China; Food Science and Nutrition Department, Nanjing Normal University, Nanjing 210097, P. R. China. Electronic address: daodongpan@163.com.
authors.forename: D D
authors.initials: DD
authors.lastname: Pan
authors.affiliation: Food Science and Nutrition Department, Nanjing Normal University, Nanjing 210097, P. R. China.
authors.forename: Z
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Food Science and Nutrition Department, Nanjing Normal University, Nanjing 210097, P. R. China.
authors.forename: T
authors.initials: T
authors.lastname: Peng
authors.affiliation: Food Science and Technology Department of the Marine Science School, Ningbo University, Ningbo 315211, P. R. China.
authors.forename: X Q
authors.initials: XQ
authors.lastname: Zeng
authors.affiliation: Food Science and Nutrition Department, Nanjing Normal University, Nanjing 210097, P. R. China.
authors.forename: H
authors.initials: H
authors.lastname: Li
mesh_terms: D000818:Animals; D002262:Carboxy-Lyases / Q000378:metabolism; D062609:Electronic Nose; D005285:Fermentation; D005516:Food Microbiology; D008401:Gas Chromatography-Mass Spectrometry; D007778:Lactobacillus / Q000378:metabolism*; D008892:Milk / Q000737:chemistry*; D025341:Principal Component Analysis; D052616:Solid Phase Extraction; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D055549:Volatile Organic Compounds; D002262:Carboxy-Lyases; C023746:acetolactate decarboxylase
keywords: Lactobacillus pentosus; electronic nose; solid-phase microextraction coupled with gas chromatography-mass spectrometry (SPME-GC-MS); volatile organic component