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Green tea and its food-grade extracts are widely used in food technology because of their rich chemical composition. Our previous study found that dynamic extraction tea extract exhibited higher quality than conventional extraction methods. Thus, the objective of this study was to develop a high-efficiency, dynamic extraction method to improve extraction efficiency and the sensory quality of green tea. The effects of dynamic extraction conditions on the chemical composition and sensory quality of green tea extract were investigated with sensory and physicochemical analysis. Extraction temperature and flow rate strongly affected the taste of green tea extract. The tea extracts were obtained with high-umami or high yield by optimized extraction conditions. The triphasic dynamic (column) extraction yield was improved by 11.22% compared with the static extraction. The results can help to understand the influences of dynamic extraction conditions on the quality of tea extract and to optimize the extraction method of tea extract. • A dynamic extraction to improve extraction efficiency and the sensory quality. • Smaller particle-size leaves increased concentrations of the chemical components. • Suitable conditions were found to produce high-umami extract with good quality. • Yield of dynamic extraction was improved 11.22% compared with static extraction. [ABSTRACT FROM AUTHOR]

Compared with the clarification method of adding Ca(OH) 2 and the traditional heating method, membrane filtration without adding Ca(OH) 2 and vacuum heating affect the aroma of brown sugar processing by reducing cations, pH and heating temperature. HS-SPME-GC-MS were used to extract and analyze volatiles formed in the production process of brown sugar (obtained by different clarification methods and heating methods), and aroma attributes were analyzed via quantitative descriptive analysis. The results showed that the green and fruity notes were higher in the brown sugar obtained by vacuum heating, especially for the samples without adding Ca(OH) 2 ; the roasted and caramel notes were enhanced by high-temperature. Meanwhile, the aroma attributes had the same tendency as the odorants. Sugarcane juice and syrup had similar volatiles compared to brown sugar. These data indicate that membrane filtration without adding Ca(OH) 2 and vacuum heating provided more fruity and green notes to brown sugar and enriched the brown sugar aroma. • GC–MS showed phenols significantly increased by vacuum heating. • Sensory profiling showed vacuum heating increased the green and fruity notes. • The samples were divided into three groups according to volatiles. • Sugarcane juice and syrup had similar volatiles. • There were more alcohols in sugarcane juice and syrups without adding Ca(OH) 2. [ABSTRACT FROM AUTHOR]

Brown sugar contains large amount of taste-active compounds. However, the effect of lime water and temperature on brown sugar processing has not been systematically studied. Herein, the NMR and e-tongue were used to analyze the taste-active compounds and taste characteristics of sugarcane juice, syrup and brown sugar. The results showed that during the clarification stage, lime water decreased phenolic acids with simple structure, but increased sugars and umami amino acids, thus increasing the sweetness and umami of sugarcane juice. However, during the evaporation stage, both lime water and high-temperature heating accelerated the Maillard reaction and caramelization of the syrup. During the concentration stage, temperature had the greatest influence on the taste in the processing of brown sugar. Under vacuum heating, it could retain more sugars, amino acids, organic acids and phenols, thus increasing sweetness and umami; meanwhile, it could reduce color, thus reducing bitterness and astringency. These data indicate that the taste-active compounds and taste characteristics of brown sugar can be improved by membrane filtration (without lime water) and vacuum heating. • In brown sugar processing, samples were obtained by changing lime water and heating. • Sweetness is the main taste of the six tastes detected by the e-tongue. • NMR showed vacuum heating significantly increased the taste-active compounds in brown sugar. • Lime water and high-temperature heating accelerated the Maillard reaction and caramelization. • Membrane filtration and vacuum heating can be applied to rich the taste of brown sugar. [ABSTRACT FROM AUTHOR]

Deep-fat fried battered and breaded foods are worldwide popular foods. In this study, egg yolk phospholipids, as well as alanine and glucose were used to generate the key odorants of fried coatings. The volatile compounds of fried coatings were extracted and analyzed by HS-SPME-GC-MS, and aroma profiles were analyzed via quantitative descriptive analysis. The results showed that the characteristic deep-fat frying odorants derived from Maillard reaction and lipids, such as methional, 2-methylbutanal and 3-methylbutanal, 2-ethyl-3,5-dimethylpyrazine, 2,4-decadienals, etc. were the highest amounts in the phospholipids & alanine and glucose treated sample, whereas the lowest in the control sample. Meanwhile, the aroma attributes had the same tendency as those of the odorants. The results proved that egg yolk phospholipids combined with alanine and glucose could be used to generate the key odorants of fried battered and breaded foods and enrich the volatile profile with a variety of Maillard reaction odorants. This treatment has a great potential use in catering industry. • Phospholipids could produce the characteristic lipid-derived odorants. • Alanine and glucose treatment could generate the typical Maillard reaction odorants. • Phospholipids combined with alanine and glucose produced key odorants simultaneously. • The aroma attributes by sensory study confirmed the rising trend of the key odorants. • Phospholipids combined with alanine and glucose is potential in deep-fat frying. [ABSTRACT FROM AUTHOR]

Cream is usually used during baking and contributes a pleasant aroma to the baked foods, but the effect of its polar components on the cream flavor is not fully understood. In this study, the polar components were extracted by using ethanol, and then were analyzed by 1H nuclear magnetic resonance (NMR). The main compositions in the extraction were lactose, phospholipids, free amino acids and free fatty acids. Then all the samples were baked at 160 °C for 30 min , respectively. GC-MS analysis showed that the polar components could generate lots of odorants, and with the addition of polar components, the lipid-derived volatile compounds in cream were significantly increased and varied, as well as Maillard reaction and caramelization products, especially butanoic acid, hexanal, (E,E)-2,4-decadienal, furfural, furaneol, maltol, methylpyrazine, 2,3-dimethylpyrazine, 2-methyl and 3-methylbutanal. On the contrary, the ethanol-treated cream sample had less odorants. Sensory analysis confirmed that the caramel and roasted notes were significantly enhanced with the addition of polar components, the ethanol-treated cream and polar components sample was similar to the cream in the attributes of milk, sweet and buttery. These data indicated that polar components in cream could be used as a functional flavor enhancer. [Display omitted] • Volatiles in heated cream were extracted and analyzed by HS-SPME-GC-MS. • Polar components extracted by ethanol were analyzed by NMR. • Polar components promote lipid oxidation, Maillard reaction and caramelization. • Polar components enhanced the 'caramel' and 'roasted' flavor of heated cream. • Polar components could be of potential use to improve the baking flavor of foods. [ABSTRACT FROM AUTHOR]