RESUMO
The technology of quick-freezing paste-coated mushrooms (Agaricus bisporus) was studied and optimized. The best microwave pretreatment condition for 1 cm slices, regarding color protection, was 5.4 W/g, for 55, 55-60 and 60 s for mushrooms with 3, 4 and 5 cm diameter caps respectively. For a batch of paste (668.2-1034.6 g), the process parameters considered were oil content (46.6-63.4 g), water content (381-562.6 g) and flour content (166-334 g) with a constant additional content of 30 g starch, 9 g baking powder, 2.6 g carrageenan, 30 g salt and 3 g pepper. These parameters were investigated using response surface methodology (RSM) with a central composite design. The optimal levels of the major paste components were 300 g flour, 432.5 g water and 50 g oil. The freezing time and sensory acceptability for paste-coated Agaricus bisporus(PCAB) under the optimized conditions were 7.49 min and 6.2 respectively. The freezing curves of PCAB were established at different temperatures and the freezing rates were calculated to find the freezing characteristics. In addition, the cell structure of PCAB, frozen at -75 °C, the lowest freezing temperature, and studied using transmission electron microscopy, was similar in quality to that of fresh Agaricus bisporus. The results suggested that Agaricus bisporus can be quick-frozen with a paste coating to produce an acceptable and nutritious convenience food.
RESUMO
Arsenic compounds are well-known toxic and carcinogenic agents, and they are widely distributed throughout the earth's crust. These compounds are associated with various human malignancies. It has been reported that there is an elevated risk of bladder cancer in an area highly contaminated with arsenic on the southwest coast of Taiwan. However, the underlying mechanisms of arsenic-associated carcinogenesis are still unclear. The cell cycle regulatory proteins are important indicators in control of cell cycle progression. Moreover, the high expression of Cyclin-D1 and loss of p16 has been associated with a worse prognosis in a variety of human cancers. Therefore, we investigated the effect of arsenic on Cyclin-D1 and p16 expression and evaluated the role of the ERK signaling pathway and DNA methylation in arsenic carcinogenesis. Our study results showed that Cyclin-D1 high expression was found in 56.3% (9/16) of urothelial carcinomas (UC) from a blackfoot disease (BFD) area and 6.3% (1/16) of UC from a non-BFD area (p=0.002). The p16 low expression in 81.2% (13/16) of UC from BFD areas was significantly lower than in non-BFD areas (25.0%; 4/16) (p=0.001). In addition, the Cyclin-D1 increased expression but decreased p16 expression in arsenite-treated SV-HUC-1 cells. However, when cells were pretreated with inhibitors (5-aza-CdR or U0126), the effects of arsenite on Cyclin-D1 and p16 expression were suppressed. Finally, these results indicated that Cyclin-D1 and p16 both might play important roles in carcinogenesis as a result of arsenic.
