Effect of lactic acid bacterial fermentation on amino acids and volatile compounds of pork trimming hydrolysate

The objective of this research was to improve the volatile flavour profile of a pork trimming hydrolysate by lactic acid bacteria (LAB) fermentation. Five probiotic strains and one dairy strain were used. The dominant aliphatic aldehydes (80.90%) in the unfermented hydrolysate were greatly reduced to <15% by converting into respective carboxylic acids and alcohols after fermentation. Strain GG was the only LAB that produced a significant level of succinic acid (1.62 mg mL⁻¹) and ketones (14.92%) (mainly diacetyl and acetoin) in the hydrolysate. Strains 299V and GG showed moderate proteolytic activities as their amino acid content reduced to 126.05 and 219.14 mg per 10 mL compared to the control (316.45 mg per 10 mL) after fermentation, respectively. However, little amino acid-derived volatiles were found in all fermented samples. These findings indicate that LAB fermentation modulates the flavour compounds of pork hydrolysates, which has the potential to be developed to novel flavouring materials.     

The impact of fermentation at elevated temperature on quality attributes and biogenic amines formation of low-salt fermented fish

To accelerate fermentation and improve quality of fermented fish, the impact of fermentation at elevated temperature on physicochemical, microbiological and flavour characteristics, as well as biogenic amines (BAs) accumulation of low-salt fermented fish was investigated. Results showed that increasing temperature at later stage significantly promoted the growth of lactic acid bacteria, retarded the reduction of yeast and increased the titratable acidity, while staphylococci and enterobacteriaceae were inhibited to higher extent when fermented at elevated temperature. BAs contents in samples fermented at 30 °C during later stage were lower than those in the group fermented at 25 °C for 28 days, and the lowest values were observed in the sample initially fermented at 25 °C for 10 days followed by fermentation at 30 °C for 18 days. Furthermore, fermentation at elevated temperature at later stage favoured the formation of desired volatile flavour compounds. Results suggested that fermentation at elevated temperature at later stage could reduce BAs accumulation and enhance quality attributes of low-salt fermented fish.     

A two‐step inoculation of Candida etchellsii to enhance soy sauce flavour and quality

Effects of novel two‐step inoculation to enhance soy sauce special flavour in Candida etchellsii were investigated at the cell growth phase. The first‐stage consists of a 5% culture inoculum of log phase cells at 30‐day. Subsequently, a 20% culture inoculum of stationary phase cells was added at 60‐day. The resulting amino nitrogen and soluble salt‐free solid yield reached 9.15 ± 0.12 and 269.60 ± 3.15 mg L^?1 in 30 °C incubator experiments, increased by 23.1% and 17.6%, respectively, as compared to the control without culture inoculation. Maximal free amino acid yield of 58.21 ± 1.77 g L^?1 was achieved, and 39 types of volatile flavour compounds content was 17.81 ± 0.45 g L^?1, which were 1.76% and 178.7% higher than the control. A novel two‐step inoculation using the C. etchellsii yeast was developed and optimised. It was proven to be a feasible reproducible process for industrial application for the improvement of the flavour and quality of soy sauce production.     

毛毡编织技艺与图案研究

毛毡的发明迎合了蒙古人游牧生活方式的特点,体现了蒙古人的审美观念,随着社会生产力的发展,其使用范围也不断扩展。文章介绍了蒙古族毛毡的历史传承及文化底蕴,并对制毡过程及毛毡编织图案做了详细介绍和分析。     

Changes in Pigments and Volatiles of Saffron ( Crocus sativusL) During Processing and Storage

Significant variations were observed in the concentration of pigments (10·0–17·0%, moisture-free basis) and flavour components during different post-harvest processing conditions of saffron (stigmas ex Crocus sativus L). The crocin pigments concentration was highest (15–17%) in the saffron samples dried between 35°C and 50°C either in a solar dryer or in an oven dryer and this also resulted in considerable reduction of normal drying time. Under these conditions the main flavouring component, safranal, was at its peak value of 60% in the oil in almost all the samples except the vacuum oven dried samples which interestingly contained 4-β-hydroxysafranal in major amounts. Studies indicated that 4-β-hydroxysafranal may be an intermediate in the formation of safranal. It was observed that prolonged storage affected the pigments and flavour concentration to a great extent, but proper packaging and storage with 5% moisture in the saffron reduced the deterioration, thereby increasing the shelflife of the product.     

Causal Effects of Aroma Compounds on Royal Gala Apple Flavours

Volatile flavour compounds produced by Royal Gala apple have been identified by GC-MS. Major components were 2-methylbutyl acetate, butyl acetate, hexyl acetate, butanol, 2-methylbutanol and hexanol. Odour-port evaluation of the components separated by GC indicated that the first four compounds were important contributors to the aroma and flavour. Use of analytical sensory panels revealed that 2-methylbutyl acetate, butanol and hexyl acetate had the greatest causal effect on those aroma and flavour attributes considered important for Royal Gala apples.     

益生菌发酵对苹果浆理化性质、抗氧化活性及挥发性风味的影响

目的 探究益生菌发酵对苹果浆理化性质、抗氧化活性及挥发性风味物质的影响。方法 测定苹果浆发酵过程中活菌数、pH、总酸、总糖、还原糖、总酚、黄酮、1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl, DPPH)自由基清除能力、铁离子还原能力(ferric reducing antioxidant power, FRAP)和2,2’-联氮-二(3-乙基-苯并噻唑啉-6-磺酸)二铵盐[2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonicacid)ammoniumsalt,ABTS]阳离子自由基清除能力,同时比较了发酵前后挥发性风味物质的变化。结果 发酵体系中活菌数、总酚、黄酮在发酵第3d时达到最大值,分别较发酵前提高了12.63%、17.63%和22.06%;FRAP与ABTS阳离子自由基清除能力在发酵第4d达到最大值,分别较发酵前提高了42.47%和10.45%;可滴定酸含量与DPPH自由基清除能力随着发酵时间的延长逐渐增加,发酵第7 d时,分别升高了126.34%和26.32%; pH、总糖、还原糖含量较...     

大豆食品豆腥味研究进展

大豆食品营养丰富,含有多种生理活性物质,但是大豆食品中往往具有不同程度的豆腥味,许多人难以接受,从而限制了大豆食品的发展和广泛食用。本文就大豆食品中豆腥味的来源以及豆腥味的消除方法进行了综述。