A Sucrose Fatty Acid Ester-mixed Emulsifier as Stabilizer of Emulsion Systems.

In the present study, the mesomorphic phase and internal structure of sucrose fatty acid ester (S1670) with cetyl alcohol mixed in different proportions was studied and assessed, within common emulsion system of cosmetics and pharmaceuticals. To characterize the system's colloidal structure the following physicochemical techniques were used: polarization microscopy, small- and wide-angle X-ray scattering (SAXS and WAXS), differential scanning calorimetry (DSC), continual and oscillatory rheology and cryogenic scanning electron microscopy (cryo-SEM). Ultimately, it was well established that there was a predominant and stable α-crystalline gel structure, formed with sucrose fatty acid ester (S1670) and cetyl alcohol, in the pseudo quarter-phase system (including squalane and aqua). In addition, the optimum ratio for α-crystalline gel formation was found to be around 61.50:38.50 (S1670 to Cetyl alcohol). Moreover, as it deviates from the critical point within a controllable range, although identical α-gel (α-form hydrated crystal) continues to exist, yet the strength and proportion in whole sample decrease with the expansion of deviation. The decent stability (which was derived from the dismatch between the lipophilic chains and the intensive hydration of -OH from S1670) and the agreeable rheological properties of the above α-gel suggest wide application in cosmetics and pharmacy in the future.

Interaction between bacterial diversity and biogenic amines production in a salted mackerel stored at soft frozen (-7℃-0℃) storage.

The bacterial diversity of salted mackerel "one-night courtyard" at soft frozen area (-7℃-0℃) storage was studied. The fish samples at 0, 14, 21, 28, and 35 days were analysis for bacterial structure using high-throughput sequencing technologies (HTS) and biogenic amines using high-performance liquid chromatography (HPLC). The analysis results of HTS showed that the dominant bacteria species was varied gradually following with storage time. On the 0th, 21st, and 28th days of storage, dominant Vibrionaceae was accounting for 71.70%, 59.16%, and 70.68% of the total sequences analyzed, respectively. On the 14th and 35th days, Shewanellaceae was the dominant bacterial, accounting for 87.53% and 70.95% of the total sequences analyzed, respectively. In addition, 21st and 28th days, an abundance of Operational Taxonomic Units (OTUs) was top. The dominant bacterial of Proteobacteria, Firmicutes, was producer of biogenic amines. Furthermore, the analysis results of HPLC shown the total biogenic amines of maximum amount 363.01 mg/kg in the sample of HY.14 lower than 1000 mg/kg of the FDA regulation. The range ability of cadaverine was obvious following with the storage time. Cadaverine was 87.36 mg/kg on the 0th day, and it was maximum amount of 276.89 mg/kg on the 14th days. Putrescine was 20 mg/kg on the 0th day and maximum amount of 55.04 mg/kg on the 28thdays of storage. The tyramine was smallest amount of production, and the largest amount was 38.99 mg/kg on 28th, and the smallest amount was 11.97 mg/kg on 35th. Nevertheless, the maximum amount of histamine was 55.04 mg/kg on the 0th day and about 23.14 mg/kg of histamine was little change from 14th to 35th days of storage. Dominant bacteria affect the change of biogenic amines. The study can help understand the interaction between microbial flora and biogenic amines in the salted mackerel of one-night courtyard.