Fungal Diversity in Xinjiang Traditional Cheese and its Correlation With Moisture Content.

Cheese is one of the traditional fermented dairy products in Xinjiang, China. Due to its geographical location and regional feature this type of cheese harbors certain regional characteristics. To investigate these, here Illumina MiSeq high-throughput sequencing technology was used to target the v4-v5 interval to analyze the composition of fungal flora in Xinjiang traditional cheese. Our results showed the fungal flora of this cheese is mainly composed of Pichia (65.20%), Kazachstania (9.05%), Galactomyces (7.21%), Zygosaccharomyces (6.56%), Torulaspora (3.13%), Dipodascus (2.11%) and Ogataea (1.64%) belonging to the Ascomycota. PcoA (Principal Co-ordinates Analysis) and an UPGMA (unweighted pair-group method with arithmetic means) based on the OTUs (Optical Transform Unit) horizontal-weighted UniFrac distances, revealed some differences in fungal community structure among 17 cheese samples. At the OTU level, nine dominant OTUs were found in all the samples, for which Pichia was the most important fungal group. Building on this, the moisture content (23.20-59.22%), water distribution, and salt content (1.13-4.84%) in cheese were also determined. We found that six of the seven dominant fungal genera had specific correlations with the above physical and chemical variables, with only Ogataea uncorrelated with any variables. The results provide a theoretical basis for the development and use of cheese microbial resources in Xinjiang, China. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12088-021-00967-x.

Effect of ultrasound on functional properties, flavor characteristics, and storage stability of soybean milk.

The effects of different ultrasound treatments (20 kHz at 400 W for 0 to 9 min) on the functional properties, flavor characteristics, and storage stability of soybean milk at 4 °C were investigated. Results indicated that non-sonicated soymilk had the maximum particle size D4, 3 of 2.47 ± 0.47 µm, while 9 min high intensity ultrasound (HIU) decreased D4, 3 to 0.44 ± 0.01 µm. 9 min of HIU decreased the total number of microorganisms in soymilk from 4.51 to 3.95 Log (CFU/mL). Moreover, 9 min HIU increased the absolute value of ζ-potential from 36.43 to 34.13 mV. Turbiscan test showed that 9 min HIU decreased the instability index of soymilk from 0.78 to 0.65. Furthermore, sensory analysis, electronic nose, electronic tongue, and gas chromatography-mass spectrometry showed that 7 min HIU decreased the content of aldehydes, furans, ketones, and alcohols by 52.09%, 75.01%, 56.79%, and 57.27%, respectively.