Influence of different drying methods on carotenoids and capsaicinoids of paprika (Cv., Jalapeno)

Influence of Refractance Window™ Drying (RWD), a novel contact drying method, on carotenoids, capsaicinoids, Retinol Activity Equivalent (RAE) and Scoville Heat Unit (SHU) of paprika (Cv., Jalapeno) was investigated in comparison with freeze drying (FD), oven drying (OD), and natural convective drying (NCD) methods. Eight carotenoids (capsanthin, capsorubin, capsolutein, β-carotene, β-cryptoxanthin, mutatoxanthin, violaxanthin and zeaxanthin) and five capsaicinoid analogues (capsaicin, dihydrocapsaicin, homodihydrocapsaicin, isodihydrocapsaicin, nordihydrocapsaicin) were identified in paprika. All these components were significantly (P < 0.05) decreased by the RWD, FD and OD methods. However, due to ongoing synthesis, the NCD method resulted in higher carotenoids, except violaxanthin and mutatoxanthin, and capsaicinoids content than those of the others, even puree. Mutatoxanthin, naturally occurring pigment in red pepper, could only be detected in FD paprika. The highest RAE and SHU values, which were derived from the data of carotenoids and capsaicinoids, respectively, were also determined in NCD paprika.     

The effect of drying method and storage on color characteristics of paprika

Discoloration and microbial proliferation are two major problems associated with production of paprika (Capsicum annuum L.) with traditional drying methods. In the present study, the Refractance Window™ drying (RWD) method was employed to dry paprika in comparison with freeze drying, hot-air oven drying, and natural convective drying methods. In order to evaluate the color quality of paprika, the reflected color parameters, extractable color, red/yellow pigment ratio, and browning index were measured immediately after drying and during three-month storage. The freeze-dried and RWD-dried paprika showed better reflected color characteristics. The highest extractable color and browning index values were recorded in naturally convective dried paprika. There was no significant difference in browning index between freeze-died and RWD-died samples. The reflected color degradation of the paprika was highly associated with brown reaction. A gradual discoloration was observed in all paprika samples during storage.     

Effects of Ultrasound, Irradiation, and Acidic Electrolyzed Water on Germination of Alfalfa and Broccoli Seeds and Escherichia coli O157:H7

ABSTRACT:  The ability of power ultrasound, acidic electrolyzed water (AEW), and gamma irradiation to inactivate Escherichia coli O157:H7 inoculated onto alfalfa and broccoli seeds was examined. The treatment conditions under which the alfalfa and broccoli seeds treated with sterile deionized water (SW), AEW, ultrasound cleaning tank (UST), ultrasound probe (USP), and irradiation (IR) would retain a germination percentage of >85% were first determined for each disinfection hurdle. E. coli O157:H7 inactivation tests were then conducted with the experimental conditions determined in the germination tests to find out the maximum inactivation ability of each disinfection hurdle. AEW treatment at 55 ^oC for 10 min reduced E. coli O157:H7 population by 3.4 and 3.3 log CFU/g for the alfalfa and broccoli seeds, respectively. IR at 8 kGy resulted in a 5-log reduction with seed germination of >85% for both seed types, but a reduction in the length and thickness of the sprouts was observed. None of the ultrasound treatments achieved over a 2-log reduction in E. coli O157:H7 population without lowering the germination to below 85%. The results of this study demonstrated that AEW and ultrasound, when applied individually or in combination with thermal treatment at 55 ^oC, were not able to deliver a satisfactory inactivation of E. coli O157:H7. A combination of several hurdles must be used to achieve a complete elimination of E. coli O157:H7 cells on alfalfa and broccoli seeds.