Unlu NZ, Bohn T, Francis DM, Nagaraja HN, Clinton SK, Schwartz SJ. Lycopene from heat induced cis-isomer rich tomato pasta sauce is more bioavailable than from all-trans rich pasta sauce in humans. Br J Nutr 2007 Jul;98(1):140-6.
Lycopene is present mainly as cis-isomers in human serum and tissues whereas all-trans-lycopene predominates in tomato products, suggesting that all-trans-lycopene is isomerised in the body or is less bioavailable. The objectives of the present study were to develop processing conditions for tomatoes to obtain products with different cis-trans-lycopene isomer distribution and to assess their bioavailability. Healthy adult subjects (n 12) were recruited for this randomised cross-over trial. Each intervention was preceded by a 2-week washout period. Two tomato sauces, one rich in all-trans-lycopene (32 center dot 5 mg total lycopene/100 g sauce; 5 % cis-isomers), the other high in cis-lycopene (26-4 mg total lycopene/100 g sauce; 45% cis-isomers), were produced by different heat-processing techniques. Each sauce (150g) was served in a standardised meal at 08.00 hours after overnight fasting. Plasma TAG-rich lipoprotein fractions over 9.5h following test-meal consumption as a measure of lycopene absorption were obtained and expressed as baseline-corrected area under the concentration v. time curves (AUC), using HPLC-electrochemical detection. AUC values adjusted for the amount lycopene consumed showed that total, total cis-, and all-trans-lycopene responses were significantly higher from the cis-isomer-rich sauce, compared with the all-trans-rich sauce, being 7 center dot 30 (SEM 1 center dot 45) v. 4 center dot 74 (SEM 1 center dot 08) nmol x 11/1 (P=0 center dot 002), 3 center dot 80 (SEM 0 center dot 76) v. 1 center dot 98 (SEM 0 center dot 37) nmol x h/1 (P=0 center dot 0005) and 3 center dot 50 (SEM 0 center dot 76) v. 2 center dot 76 (SEM 0 center dot 76) nmol x h/1 (P=0 center dot 01), respectively. The present study demonstrates significant lycopene bioavailability from cis-lycopene-rich tomato sauce and highlights the importance of considering isomer-distribution for lycopene bioavailability. Furthermore, processing parameters can be controlled to alter isomer patterns of tomato products and influence lycopene bioavailability.
Jing P, Giusti MM. Effects of extraction conditions on improving the yield and quality of an anthocyanin-rich purple corn (Zea mays L.) color extract. J Food Sci 2007.
Purple corn (Zea mays L.) is a rich and economic source of anthocyanin colorants and funtional ingredients. However, high levels of anthocyanin-rich waste are generated during processing, reducing the yields and increasing the costs of the final product. This waste has been associated with anthocyanin complexation with tannins and proteins. Our objective was to evalutate anthocyanin extraction methods to reduce purple corn waste. Different solvents (water, 0.01%-HCl-acified ethanol), temperatures (room temperature, 50, 75, and 100 degrees C), and times of exposure to the solvents were investigated. Acetone (70% acetone in water) extraction was used as control. Anthocyanins, total phenolics, tannins, and proteins in extracts were measured by the pH differential, Folin-Ciocalteu, protein precipitation, and BCA assay methods. Qualitative analyses were done by HPLC coupled to a PDA detector and SDS-PAGE analysis. Water at 50 degrees C achieved the highest yield of anthocyanins (0.94 +/- 0.03g per 100 g dry cornob) with relatively low tannins and proteins, comparable to the anthocyanin yield of anthocyanin yield obtained by 70% acetone (0.98 +/- 0.08 g per 100g dry cornob). Extending the extraction time for 20 to 60 min and using consecutive reextraction procedures reduced anthocyanin purity, increasing the yields of other phenolics. A neutral protease was applied to the extracts and effectively decomposed the major protein that was believed to contribute to the development of anthocyanin complexion and waste generation. Extraction time, consecutive reextraction procedures, and enzyme hydrolysis should be considered for highly yield of anthocyanins and waste reduction.
Li SQ, Zhang HQ, Balasubramaniam VM, Lee YZ, Bomser JA, Schwartz SJ, Dunne CP. Comparison of effects of high-pressure processing and heat treatment on immunoactivity of bovine milk immunoglobulin G in enriched soymilk under equivalent microbial inactivation levels. J Agric Food Chem 2006.
Immunoglobulin-rich foods may provide health benefits to consumers. To extend the refrigerated shelf life of functional foods enriched with bovine immunoglobulin G (IgG), nonthermal alternatives such as high-pressure processing (HPP) may offer advantages to thermal processing for microbial reduction. To evaluate the effects of HPP on the immunoactivity of bovine IgG, a soymilk product enriched with milk protein concentrates, derived from dairy cows that were hyperimmunized with 26 human pathogens, was subjected to HPP or heat treatment. To achieve a 5 log reduction in inoculated Escherichia coli 8739, the HPP or heat treatment requirements were 345 MPa for 4 min at 30 degrees C or for 20 s at 70 degrees C, respectively. To achieve a 5 log reduction in natural flora in the enriched soymilk, the HPP or heat treatments needed were 552 MPa for 4 min at 30 degrees C or for 120 s at 78.2 degrees C, respectively. At equivalent levels for a 5 log reduction in E. coli, HPP and heat treatment caused 25% and no detectable loss in bovine IgG activity, respectively. However, at equivalent levels for a 5 log reduction in natural flora, HPP and heat resulted in 65 and 85% loss of bovine IgG activity, respectively. Results of combined pressure-thermal kinetic studies of bovine milk IgG activity were provided to determine the optimal process conditions to preserve product function.
Riedl KM, Zhang YC, Schwartz SJ, Vodovotz Y. Optimizing dough proofing conditions to enhance isoflavone aglycones in soy bread. J Agric Food Chem 2005.
Native beta-glucosidase activity in soy bread can convert isoflavone glucosides to aglycones during proofing, and this study determined the time-temperature dependence of this process. Samples were taken every hour for 4 h during proofing at 22, 32, and 48 degrees C to determine beta-glucosidase activity and isoflavone profiles of the dough. After 1-2 h, the beta-glucosidase activity increased 43-84% achieving a plateau value at 22 degrees C but declining when proofed beyond 2 h at 32 degrees C and 48 degrees C. Large increases in aglycones and corresponding decreases in the simple glucosides were observed during proofing. The level of malonyl-glucosides decreased 3-15%, and acetyl-glucosides were fairly constant. The two higher temperatures drove more rapid conversion: 70-73% of simple glucosides in 2-4 h. The extent of conversion in the early proofing periods corresponded to beta-glucosidase activity. The optimum time-temperature protocol was 2 h at 48 degrees C resulting in a rapid, high conversion.