Extraction Characteristics of Anthocyanins from Preliminarily-processed Products of Purple Sweet Potatoes during the Gelatinization Process

Objective] This study aimed to investigate the method for efficient utilization and development of purple sweet potatoes. [Method] Purple sweet potatoes were dried at two specific temperatures and prepared into preliminarily-processed products for gelatinization simulation to analyze the extraction amount of anthocyanins from gelatinized samples at different gelatinization stages. [Result] During the gelatinization process, the extraction rate of anthocyanins from purple sweet potato samples reached the highest as the temperature rised from 90 ℃ to 95 ℃,and the extraction amount of anthocyanins reached the maximum at 15 min postheat preservation at 95 ℃. Purple sweet potato samples dried at 60 ℃ exhibited larger retention amount, larger maximum extraction amount and higher maximum extraction rate of anthocyanins compared with those dried at 110 ℃. [Conclusion] Drying at low temperatures and appropriately shortening the initial gelatinization stage below 90 ℃ is conducive to the retention and extraction of anthocyanins from purple sweet potatoes.

Investigation on the Appropriate Dose of ^(60)Co-γ Irradiation for Tubers of Purple Sweet Potato

[Objective] This study aimed to investigate the appropriate dose of 60^Co-γ irradiation for tubers of purple sweet potato.[Methods] The tubers of two purple sweet potato varieties Xuzi L-7 and Yuenanzi were used as experimental materials,and treated with 60^Co-γ irradiation at different doses（0,25,50,75,100,125 and 150 Gy） to determine the emergence rate,number of emerged seedlings per tuber and fresh weight per seedling.[Results] After the 60^Co-γ irradiation at different doses,the emergence period of tubers was postponed while the emergence rate,number of emerged seedlings per tuber and fresh weight per plant were decreased,and the differences between different varieties and different irradiation doses reached significance level.Compared with the control,the emergence period of tubers at irradiation doses above 25 Gy were postponed by 2,3,5,6 and 12 d,respectively.[Conclusion] The half lethal dose（LD50） of Xuzi L-7 was 66.73 Gy,and that of Yuenanzi was 74.96 Gy.

Screening and Evaluation of Different Purple Sweet Potato Varieties Specially Used for Processing

Objective] This study almed to screen high-quality and high-yield purpIe sweet potato varieties special y used for processing which were suitabIe for pIanting in Liancheng County. [Method] By using a randomized bIock design, with ‘Longyan 7-3’ as a controI, five purpIe sweet potato varieties were introduced in the autumn of 2012 for comparaton test to evaluate agronomic tralts, economic characters, nu-tritional quality, and processing quantity of dried sweet potato products and fried chips. [Result] ‘Weixiang No.1’ exhibited the highest yield of 41.9 t/hm2, which was improved by 25.8% compared with ‘Longyan 7-3’; fresh tuber yield of ‘Jishu No. 18’ reached 31.6 t/hm2, which was simiIar to that of ‘Longyan 7-3’; dried sweet potato products of ‘Jishu No.18’ and ‘Weixiang No.1’ not onIy had simiIar process stabiIity, taste and coIor to ‘Longyan 7-3’, but also exhibited exceI ent morphoIogy, coIor, transparency, taste and texture, which indicated that these two purpIe sweet potato varieties were suitabIe for processing dried sweet potato products; fried sweet potato chips of ‘Jishu No.18’ and ‘Weixiang No.1’ had moderate oiI content, high expansion degree and simiIar quality to ‘Longyan 7-3’, which indicated that these two purpIe sweet potato varieties were suitabIe for processing fried sweet potato chips; ‘Fushu No.9’, ‘Quanzi No.1’ and ‘Ninzi No.1’ exhibited beautifuI shape, high nutritional quality and good eating quality, which were suitabIe for fresh eating or processing sweet potato powder. [Conclusion] This study provided a scientific ba-sis for Iarge-scale popuIarization and appIication of new purpIe sweet potato vari-eties special y used for processing.

Consumption of purple sweet potato leaves modulates human immune response: T-lymphocyte functions, lytic activity of natural killer cell and antibody production

AIM： To study the immunological effects of physiologica doses of purple sweet potato leaves （PSPL）. METHODS： The randomized crossover study （two periods, each lasting for 2 wk） involved 16 healthy non-smoking adults of normal weight. The 6-wk study consisted of a run-in （wk 1） PSPL diet （daily consumption of 200 g PSPL） or a control diet （low polyphenols, with the amount of carotenoids adjusted to the same level as that of PSPL） （wk 2-3）, washout diet （wk 4）, and switched diet （wk 5-6）. Fasting blood was collected weekly in the morning. T-lymphocyte function was assessed via the proliferation and secretion of immunoreactive cytokines. Salivary IgA secretion and the specific cytotoxic activities of cytotoxic T lymphocytes and natural killer （NK） cells were determined. RESULTS： The plasma 13-carotene level increased with time in both groups, while the plasma polyphenol level decreased in the control group, and no significant difference was detected between the two groups. Although p^asma polyphenol levels did not significantly increase in the PSPL group at the end of the study, they were significantly elevated in urine. PSPL consumption produced a significant increase in proliferation responsiveness of peripheral blood mononuclear cells （PBMC） and their secretion of immunoreactive IL-2 and IL-4. As well, lytic activity in NK cells was elevated in a time-dependent fashion. Salivary IgA secretion significantly decreased in control group after 2 wk, and returned to baseline following dietary switch to PSPL. CONCLUSION： Consumption of PSPL modulates various immune functions including increased proliferation responsiveness of PBMC, secretion of cytokines IL-2 and IL-4, and the lytic activity of NK cells. The responsible determinants of PSPL remain to be elucidated, as does the biological significance of the present observations.

Regulation of Anthocyanin during Storage Root Development Stage in Sweet Potato(Ipomoea batatas(L.) Lam.)

Anthocyanin accumulation during storage root development in purple-fleshed sweet potato was analyzed by detection of anthocyanin concentration, accumulation rate and the expression pattern of anthocyanin biosynthetic genes by semi-quantitative RT-PCR. Anthocyanin concentration in sweet potato cvs Jishu 18 and Ayamurasaki increased steadily during storage root development stage. The accumulation rate in two genotypes peaked at 50 to 65 d after transplanting, and then declined rapidly. During storage root development of Ayamurasaki, the anthocyanin biosynthesis gene, IbCHS, was constitutively expressed, the genes IbF3H, IbDFR, IbANS were induced steadily, reaching a maximum at the later stage of root thickening, and IbPAL steadily decreased. Therefore, the mechanism of anthocyanin accumulation differed between the two cultivars, and anthocyanin biosynthesis was regulated through regulation of its synthetic enzymes.

Diacylated anthocyanins from purple sweet potato(Ipomoea batatas L.)attenuate hyperglycemia and hyperuricemia in mice induced by a high-fructose/high-fat diet

Studies have shown that targeting xanthine oxidase(XO)can be a feasible treatment for fructose-induced hyperuricemia and hyperglycemia.This study aimed to evaluate the dual regulatory effects and molecular mechanisms of diacylated anthocyanins from purple sweet potato(diacylated AF-PSPs)on hyperglycemia and hyperuricemia induced by a high-fructose/high-fat diet.The body weight,organ index,serum biochemical indexes,and liver antioxidant indexes of mice were measured,and the kidneys were observed in pathological sections.The relative expression levels of messenger RNAs(mRNAs)of fructose metabolism pathway enzymes in kidney were detected by fluorescent real-time quantitative polymerase chain(qPCR)reaction technique,and the expression of renal transporter protein and inflammatory factor pathway protein was determined by immunohistochemistry(IHC)technique.Results showed that diacylated AF-PSPs alleviated hyperuricemia in mice,and that this effect might be related to the regulation of liver XO activity,lipid accumulation,and relevant renal transporters.Diacylated AF-PSPs reduced body weight and relieved lipid metabolism disorder,liver lipid accumulation,and liver oxidative stress,thereby enhancing insulin utilization and sensitivity,lowering blood sugar,and reducing hyperglycemia in mice.Also,diacylated AF-PSPs restored mRNA levels related to renal fructose metabolism,and reduced kidney injury and inflammation.This study provided experimental evidence for the mechanisms of dual regulation of blood glucose and uric acid(UA)by diacylated AF-PSPs and their utilization as functional foods in the management of metabolic syndrome.