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In this study, the wild type 6421 and the fruit color mutant E55 of pepper were evaluated for fruit color, pigment contents and quality components at different developmental stages. The results demonstrated that the fruit color of 6421 and E55 changed from green to yellow and then to red, and from green to brown and then to orange, respectively, as the fruit developed from mature green to ripe. For both 6421 and E55, the color parameters a* and C* increased, while hue angle (h) value decreased. Furthermore, chlorophyll (Chl) content declined, whereas carotenoid (Car) content increased. Additionally, the contents of VC, soluble sugar, soluble protein and capsaicin increased, while cellulose content decreased. At the mature green stage, there was no significant difference between 6421 and E55 in five color parameters (L*, a*, b*, C*, and h values), Chl and Car contents or six quality indicators (cellulose, VC, soluble sugar, soluble protein, and capsaicin contents) (P > 0.05). During the color-turning to ripening stages, L*, b* and C* values and VC and soluble sugar contents were significantly higher and soluble protein and cellulose contents were significantly lower in E55 than in 6421 (p 0.05). Correlation analysis showed that for both 6421 and E55, Chl and Car contents were significantly or extremely significantly correlated with each quality parameter except for cellulose content. Among the tested quality indicators, soluble sugar, soluble protein, and capsaicin contents were significantly or extremely significantly positively correlated with each other, while cellulose content was significantly or highly significantly negatively correlated with the other indicators. This study can serve as a theoretical basis for research on the coloration mechanism of peppers as well as for the screening and breeding of high-quality pepper cultivars.

Salt content is essential for the quality of aquatic products, especially for the water-holding capacity and textural properties of salted products and the gel properties of surimi-based products. However, the salt content in traditional aquatic products is generally too high to meet consumers’ demand for healthy convenience foods with low salt content. Reducing the salt content will decrease the storage stability, eating quality and processing properties of aquatic products. Therefore, reducing the salt content without sacrificing the quality is an important issue faced by the aquatic product processing industry. The premise and basis of effectively controlling the quality of aquatic products with low salt content is to clarify the effect and mechanism of NaCl on the quality of aquatic products. In the present paper, we review the role of NaCl in the processing and storage of aquatic products and the latest progress of salt reduction technologies from the aspects of NaCl substitution, novel salt reduction technologies, and sodium release/perception enhancement technologies, and we discuss the problems with the processing of salt-reduced aquatic products. The present article may provide valuable information for high-quality processing of lightly salted aquatic products.

Simple Summary: This study investigated the relationship between feed particle size and growth performance or nutritional composition of crayfish (Procambarus clarkii) larvae. Our results showed that appropriate feed particle size could promote the growth and improve the nutritional value of crayfish. The critical values of suitable particle sizes for SGR and FCR were achieved at 0.55 mm and 0.537 mm. When the particle size of the feed exceeded 0.55 mm and 0.588 mm, the growth of crayfish reached the highest value and the FCR was the lowest. Where the feed particle size exceeds 0.55 mm and 0.588 mm, the growth and feeding of crayfish are unaffected. Compared to other groups, group C has the highest nutritional value. Therefore, we recommend that the appropriate food size for juvenile crayfish is 0.71–0.85 mm (group C). A suitable feed size has a positive effect on animal feeding. For aquatic larvae, the correct feed size is very important for their growth. This experiment analyzed and compared the effect of different particle sizes of feed for larval stages on the growth performance, whole body composition, and muscle amino acid and fatty acid composition of crayfish. Five larval crayfish diets of different particle sizes, namely < 0.40 mm (Group A, control group), 0.40–0.50 mm (Group B), 0.71–0.85 mm (Group C), 0.90–1.00 mm (Group D) and 1.5 mm (Group E), were fed to 2000 crayfish (initial weight 0.0786 ± 0.0031 g) for 100 d. The results showed that as the particle size increased, final weight, weight gain (WG, p = 0.001) and specific growth rate (SGR, p = 0.000) of the crayfish tended to increase and then leveled off, with the control group being the lowest. The feed conversion ratio (FCR, p = 0.000) showed a decreasing and then equalizing trend with increasing particle size, but there was no significant difference between the groups except the control group. Broken-line regression analysis showed that the critical values for the appropriate particle feed size for crayfish larvae were 0.55 mm and 0.537 mm using SGR and FCR as indicators. Groups B, C and D had the highest crude protein content and were significantly higher than the control group (p = 0.001). Group E had the highest umami amino acid (UAA) and was significantly higher than the control group (p = 0.026). The content of isoleucine (Ile, p = 0.038) and phenylalanine (Phe, p = 0.038) was highest in group C and significantly higher than in the control group. Through principal component analysis, groups C and D were shown to contain leucine (Leu), glutamic (Glu), methionine (Met), valine (Val), histidine (His), Phe, and Ile levels significantly induced. The content of linoleic acid (C18:2n6, p = 0.000), linolenic acid (C18:3n3, p = 0.000), saturated fatty acid (SFA, p = 0.000), monounsaturated fatty acid (MUFA, p = 0.001), polyunsaturated fatty acid (PUFA, p = 0.000) and n-6 PUFA (p = 0.000) in group C was the highest and significantly higher than the control group. Principal component analysis showed that group C significantly induced the levels of C18:2n6, C18:3n3, DHA, EPA, n-3 PUFA and n-6 PUFA in muscle. Therefore, our results suggest that appropriate feed particle size can improve the growth performance and nutrient composition of crayfish. Based on the broken-line regression analysis of SGR and FCR, the critical values of optimal particle size for crayfish are 0.55 mm and 0.537 mm, and when the particle size exceeds these critical values (not more than 1.5 mm commercial feed), growth performance and FCR of the crayfish are no longer changed. Nevertheless, group C has high protein and low lipid content, as well as better nutrition with amino acids and fatty acids. Overall, combined with growth performance and nutrient composition, it is recommended that the particle size of the diet at the larval stage for crayfish is between 0.71 and 0.85 mm. [ABSTRACT FROM AUTHOR]

The reduction of CO2 is an important method to produce chemicals such as methanol, formic acid, formaldehyde, etc. In general, the reduction of CO2 is carried out at high temperatures and pressures with precious metals as catalysts, which is not favorable for industrial procedures. Thus, it will be very useful if researchers can find cost-effective catalysts for industrial application in CO2 reduction. In this work, commercially available ethylenediaminetetraacetic acid (EDTA) was tested as a cheap, non-toxic, and recyclable catalyst to initiate the N-carbonylation reaction of CO2 with amines. After screening various reaction parameters, including temperature, pressure, time, solvent, and reducing agent, the optimal reaction conditions were obtained: 80 °C, 2 MPa, 6 h, 50 mmol% catalyst dosage, 1 mL DMSO, and 1:1 molar ratio of amine to reducing agent. Notably, further studies confirmed that EDTA could also be effective for N-formylation even under ambient conditions (0.1 MPa and room temperature). The suitability of the catalyst for 26 kinds of substrates (including aliphatic amines, aromatic amines, and alicyclic amines) and its reusability were also investigated, with satisfactory results. Scale-up research has been performed effectively with a high conversion of amine (83%) to obtain the mono-formylated product selectively. Finally, the mechanism of the reaction between amine and CO2 has been proposed via control experiments and compared with results in the literature. [ABSTRACT FROM AUTHOR]