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In this study, we evaluated the cis/trans-lycopene content in commercial ketchup, and investigated the effect of cooking of fermented tomato sour soup added with one of seven oils including peanut oil (PO), sesame oil (SO), corn oil (CO), tung seed oil (TSO), olive oil (OO), Litsea cubeba oil (LCO), and mustard oil (MO) on lycopene isomerization. The results showed significant differences in the contents of total lycopene and cis-lycopene among six brands of ketchup (P < 0.05), with cis-lycopene accounting for only 20.84%-24.56% of the total lycopene. The contents of total lycopene and cis-lycopene were significantly different among the seven cooked fermented tomato sour soup samples (P < 0.05), and their proportions of cis-isomers (51.40%-78.23%) were 1.2-1.9 times higher than that of the blank group and 2.09-3.75 times higher than those of the six brands of ketchup. Specifically, the sample with added MO had the highest proportion of cis-lycopene (78.23%), followed by those with SO and PO (75.34% and 71.65%, respectively). The total lycopene and cis-lycopene contents of the sample with added PO were 6.6 and 11.4 times higher than those of the blank control group, respectively, indicating that the former has great market potential. Therefore, the results of this study could provide a scientific basis for the further processing of fermented tomato sour soup for high-value functional products.

Red sour soup is a Guizhou specialty condiment made by the natural fermentation of tomatoes and chili. In this study, three components (tomato acid, chili acid, and tomato and chili mixed acid) of split‐fermented red sour soup were explored to compare the quality characteristics and microbial communities in the middle and late fermentation stages. The titratable acidity of mixed acids was lower than that of tomato acid and chili acid in the middle stage, but it was significantly increased in the late stage. The cell viability of lactic acid bacteria was mostly higher than that of yeasts during the whole fermentation. Also significantly increased in the late stage of fermentation were sensory scores and the signal intensity of sour substances. However, the signal intensity of both bitter and salty substances decreased, and the total amount of free amino acids was reduced. In addition, the antioxidant capacity of the samples and the dominant microorganisms were different between the two fermentation stages, Lactobacillus and Kazachstania were the key common genus of the different components of split‐fermented red sour soup. It is anticipated that this study would provide us an insight into the quality characteristics and microbial communities of split‐fermented red sour soup. [ABSTRACT FROM AUTHOR]

Chloroprene rubber (CR) is frequently quoted as an example of strain‐induced crystallizing elastomer. Many researchers have focused on studying the aging mechanism and mechanical properties of aged CR, little has been done on the effect of crosslinking structure on strain‐induced crystallization (SIC). The present paper related systematic investigations combining the changes of crosslinking structure and its influence on SIC. It was firstly investigated based on FTIR, crosslinking density test and GPC. The results showed that the molecular chains were oxidized in the early stage of aging, but the crosslinking reaction still dominated. At the same time, sol content and polydispersity decreased. In the later stage of aging, CR was oxidized, resulted in severe molecular chains fracture and an increase in the free sol content and polydispersity. The impact of aging on SIC under tensile condition was further investigated by the tensile tests. An obvious stress‐hardening was found for unaged CR, but not in aged CR. The crystallinity and microcrystalline region orientation tests showed that oxidation, crosslinking by double bonds and dechlorination during aging were not conducive to the orientation of molecular chains during stretching. It is the aging process that has an adverse effect on the SIC of CR. [ABSTRACT FROM AUTHOR]