Abstract Melanin pigments have great application value and development potential in food industry to use as nature functional food colorants. In initial study, twenty-two Auricularia auricula strains were screened for stronger production ability of melanin pigments by solid culture. Three A. auricula strains (RF201, QD2 and QD6) with higher pigment production capacity were selected for further study through submerged culture supplementing 1 g/L l-tyrosine. The maximal pigment yields of A. auricula RF201, QD2 and QD6 were 493.9, 367.6 and 318.5 mg/L, respectively. Among three strains, A. auricula RF201 possessed the strongest production ability of melanin pigments. The present study indicated that A. auricula RF201 could be used as potential excellent producer of melanin pigments.

Abstract Effect of sonication on the blueberry juice was studied by evaluating the pH, viscosity, electric conductivity, color, total sugars, soluble solids, polyphenol, anthocyanidin, and radical scavenging activities. There were not any remarkable (p > 0.05) change in pH and electric conductivity. However, viscosity and color of blueberry juice markedly (p < 0.05) enhanced with the extension of sonication time. Meanwhile, total sugars, soluble solids, polyphenol, and anthocyanidin were obviously enhanced (p < 0.05). Moreover, prominent increase (p < 0.05) was observed on DPPH, superoxide, and hydroxyl radicals scavenging activities of sonicated blueberry juice. The current results exhibited sonication effectively improved blueberry juice quality and enhanced its antioxidant activity.

Abstract Growth of Enterobacter aerogenes and accumulation of histamine in chub mackerel (Scomber japonicus) were investigated through measuring bacterial count, histidine decarboxylase (HDC) activity and histamine content in fish samples stored at various temperatures from 4 to 37 °C. Results showed that bacterial count and HDC activity rapidly increased in chub mackerel inoculated with E. aerogenes at storage temperature above 20 °C and reached the highest values (8.64 log CFU/g and 31.68 U/g) at 37 °C. Meanwhile, fish samples stored at 25 and 37 °C for 18 h, formed histamine at above 50 mg/100 g of the potential hazard level. In contrast, bacterial growth and histamine formation were controlled for 36 h by cold storage at low temperature (4 °C). Therefore, strict temperature control was necessary for preservation and processing of chub mackerel in order to assure this marine fish safety.

Abstract Melanin is a natural high molecular weight pigment with the huge application value and development potential in food industry. In the present study, medium composition for melanin production by fungus Auricularia auricula was investigated. Wheat bran extract, l-tyrosine, and CuSO4 were determined to optimize medium composition by response surface methodology with Box–Behnken design. Results indicated that the optimal medium composition was 26.80% (v/v) wheat bran extract, 1.59 g/L l-tyrosine, and 0.11 g/L CuSO4, and the maximum melanin yield was 519.54 mg/L. Melanin production through A. auricula fermentation avoided expensive enzymatic or complicated chemical methods for melanin extraction from tissues of plant or animal, which had the huge application value and development potential for efficient production of melanin.

Effect of ultrasound treatment on carrot juice was investigated through measuring pH, electrical conductivity, viscosity, visual color, total soluble solids, total sugars, total carotenoids, ascorbic acid contents and microbial load. No significant effect (p>0.05) of ultrasound treatment on pH of carrot juice was observed. Electrical conductivity, viscosity and color values gradually increased (p<0.05) with treatment time increase. Total soluble solids, total sugars, total carotenoids and ascorbic acid contents of carrot juice were significantly improved (p<0.05) due to ultrasound treatment. Moreover, significant decrease (p<0.05) in microbial load of sonicated carrot juice was observed. Results from present study suggested that ultrasound treatment could improve quality and safety of carrot juice.

Chemical composition and nutritive value of hot pepper seeds (Capsicum annuum) grown in Northeast Region of China were investigated. The proximate analysis showed that moisture, ash, crude fat, crude protein and total dietary fiber contents were 4.48, 4.94, 23.65, 21.29 and 38.76 g/100 g, respectively. The main amino acids were glutamic acid and aspartic acid (above 2 g/100 g), followed by histidine, phenylalanine, lysine, arginine, cysteine, leucine, tryptophan, serine, glycine, methionine, threonine and tyrosine (0.8-2 g/100 g). The contents of proline, alanine, valine and isoleucine were less than 0.8 g/100 g. The fatty acid profile showed that linoleic acid, palmitic acid, oleic acid, stearic acid and linolenic acid (above 0.55 g/100 g) as the most abundant fatty acids followed lauric acid, arachidic acid, gondoic acid and behenic acid (0.03-0.15 g/100 g). Analyses of mineral content indicated that the most abundant mineral was potassium, followed by magnesium, calcium, iron, zinc, sodium and manganese. The nutritional composition of hot pepper seeds suggested that they could be regarded as good sources of food ingredients and as new sources of edible oils.

AbstractThe extraction conditions (liquid-solid ratio, temperature and time) of antioxidant polysaccharides from Auricularia auricula fruiting bodies (AAFB) were optimized using response surface methodology (RSM). The Box-Behnken experimental results showed the optimum extraction conditions as follows: a liquid-solid ratio of 38.77 mL/g, a temperature of 93.98 °C and a time of 3.41 h. Under these conditions, the maximal polysaccharide yield was 10.46 g/100 g. In addition, AAFB polysaccharides exhibited stronger antioxidant activities by evaluating of Fe2+-chelating ability and hydroxyl radical scavenging activity with IC50 values of 0.43 and 0.38 mg/mL, respectively. These results indicated that AAFB polysaccharides might be potentially used as a natural antioxidant.

Melanin extracted from Auricularia auricula fruiting bodies (AAFB) was examined by element analyzer, amino acid analyzer, inductively coupled plasma-optical emission spectrometry. Elemental composition analysis revealed that main component of AAFB melanin was pheomelanin. Amino acid analysis showed that 16 amino acids were found in AAFB melanin and total amino acid content was 321. 63 mg/g. There were 13 detectable metal elements in AAFB melanin, which was rich in Ca, Fe, Cu and Zn. In addition, AAFB melanin exhibited stronger scavenging activities on 2,2-diphenyl-l-picrylhydrazyl (DPPH) radical, superoxide radical and hydroxyl radical with IC50 values of 0.18, 0.59 and 0.34 mg/mL, respectively. These results indicated that AAFB melanin might be potentially used as a natural antioxidant.