Kejing An

Comparison of different drying methods on Chinese ginger (Zingiber officinale Roscoe): Changes in volatiles, chemical profile, antioxidant properties, and microstructure.

Nowadays, food industry is facing challenges in preserving better quality of fruit and vegetable products after processing. Recently, many attentions have been drawn to ginger rhizome processing due to its numerous health promoting properties. In our study, ginger rhizome slices were subjected to air-drying (AD), freeze drying (FD), infrared drying (IR), microwave drying (MD) and intermittent microwave & convective drying (IM&CD). Quality attributes of the dried samples were compared in terms of volatile compounds, 6, 8, 10-gingerols, 6-shogaol, antioxidant activities and microstructure. Results showed that AD and IR were good drying methods to preserve volatiles. FD, IR and IM&CD led to higher retention of gingerols, TPC, TFC and better antioxidant activities. However, FD and IR had relative high energy consumption and drying time. Therefore, considering about the quality retention and energy consumption, IM&CD would be very promising for thermo sensitive material.

Effect of Osmotic Dehydration with Pulsed Vacuum on Hot-Air Drying Kinetics and Quality Attributes of Cherry Tomatoes

The effects of osmotic dehydration (OD) with or without pulsed vacuum (PV) on hot-air drying kinetics and quality attributes of cherry tomatoes were investigated. Both OD and PVOD pre-treatments were performed for 3 h at 50°C in 50 and 70o Brix sucrose solutions with a solution-to-fruit mass ratio of 4:1, and PVOD was applied for 15 min before OD at atmospheric pressure. Samples were further dried at air temperature of 70°C. Effective moisture diffusivity (D eff) of osmotically dehydrated samples increased gradually while the Deff curve of fresh samples had a plateau stage during hot air drying. Lower glass transition temperature, Tg, values of osmotically dehydrated samples indicated that they needed a lower storage temperature. Both OD and PVOD pre-treatments had advantages in shortening drying cycles and improving quality of products. Compared with air drying, osmo-air drying decreased the total drying time, color change, and hardness of dried samples by 32.26%, 18.11%, and 88.21%, respectively, and increased volume ratio and vitamin C retention rate by 72.31% and 125.82%. As compared with OD, PVOD decreased color change and hardness by 28.48% and 45.17%, increased volume ratio and vitamin C retention rate by 27.41% and 17.77%, but there was no significant difference shown in drying time. Therefore, osmotic pre-treatment can shorten the total dehydration time, and improve the general quality of dried cherry tomatoes.

Chemical Constituents from Pericarpium Citri Reticulatae

Abstract Objective To study the chemical constituents from Pericarpium Citri Reticulatae (Citrus reticulata). Methods The chemical constituents were isolated and purified by silica gel column, Sephadex LH-20, and ODS column chromatography. The structures were identified by spectral data. Results Nineteen compounds were isolated and identified as 4′,5,6,7-tetramethoxyflavone ( 1 ), 3,3′,4′,5,6,7,8-heptmethoxyflavone ( 2 ), sinensetin ( 3 ), 5- O -demethylnobiletin ( 4 ), tangeretin ( 5 ), nobiletin ( 6 ), apigenin ( 7 ), 5- O -desmethyltangeretin ( 8 ), 5,7-dihydroxy-3,3′,4′,6-tetramethoxyflavone ( 9 ), pachypodol ( 10 ), 4′,5,6,7-tetramethoxyflavanone ( 11 ), 3′,4′,5,7,8-pentamethoxyflavanone ( 12 ), agestricin C ( 13 ), scoparone ( 14 ), isoscopoletin ( 15 ), hesperidin ( 16 ), didymin ( 17 ), methylhesperidine ( 18 ), and naringin ( 19 ). Conclusion Compounds 9-15 are obtained from this plant for the first time.