Studies on “sugar-reactivity” of agars extracted from some Indian agarophytes

Sugar reactivity was observed within the sugar–agar complexes in presence of sucrose and glucose with agars of Indian agarophytes viz. Gelidiella acerosa, Gracilaria edulis, Gracilaria crassa and Gelidium pusillum. The sugar reactivity was more pronounced in presence of sucrose than glucose. Oxoid agar was used as the reference material. Control agar gel contained 1.12% agar (w/w) in water. Sucrose–agar and glucose–agar gels in water consisted of 50% (w/w) sucrose and 50% (w/w) glucose, respectively along with 1.12% (w/w) agars of the four seaweeds mentioned above. Addition of sucrose resulted in increase (ca. 25–45%) in gel strength; increase (2–3 °C) in gelling and melting temperatures was observed in the gels prepared with agars from all the agarophytes and Oxoid agar. On the other hand, addition of glucose resulted in increase (19–34%) in the gel strength and gelling and melting temperatures of the agar gels of Oxoid as well as of all other agars decrease (2–3 °C). Maximum sugar reactivity was observed with the 50% level of sucrose and glucose in agar gels. Rheological and thermogravimetric characteristics of these gel samples were studied. The latter showed two patterns e.g. control agar gel of Oxoid agar was thermally less stable than the four control agar samples studied; in sugar–agar gel samples it followed a reverse pattern. To our knowledge, this is the first report of “sugar reactivity” of agar of Indian agarophytes. Sugar reactivity of agar in presence of glucose is also reported for the first time. The results of this study will be useful in bioprospecting as well as in exploring new applications.     

Effect of temperature and concentration on Rheological properties of “Kesar” mango juice

Flow characteristics of juice of “Kesar” mango have been investigated and rheological parameters were evaluated using rotational viscometer at temperature 20, 30, 40, 50, 60 and 70°C at concentration of 7.6%, 11.69%, 16.37% and 26% total solid. The experimental results followed the power law model for the best fit and the values of flow behaviour index (n) was less than unity (0.20–0.33) at all temperature and concentration revealing the shear-thinning (pseudoplasticity) nature of juice. An obvious correlation between consistency coefficient, in the range of 0.32–80.09 Pa sⁿ and inverse absolute temperature has been exhibited by Arrhenius model. Power equation indicated that consistency coefficient increased non-linearly with increase in concentration. The magnitude of activation energy were found in the range of 3.8–13.7 kJ/mol K.     

Phenolic Fractions from Muscadine Grape “Noble” Pomace can Inhibit Breast Cancer Cell MDA‐MB‐231 Better than those from European Grape “Cabernet Sauvignon” and Induce S‐Phase Arrest and Apoptosis

Tons of grape pomace which still contained a rich amount of plant polyphenols, is discarded after winemaking. Plant polyphenols have multi‐functional activities for human body. In this study, polyphenols of pomaces from Muscadinia rotundifolia “Noble” and Vitis vinifera “Cabernet Sauvignon” were extracted and fractionated, and then they were analyzed with LC‐MS and the inhibitory effects on breast cancer cells were compared. The inhibition on MDA‐MB‐231 cells of fractions from “Noble” was further evaluated. The results showed that polyphenols from 2 grape pomaces could be separated into 3 fractions, and ellagic acid and/or ellagitannins were only detected in fractions from “Noble” pomace. All 3 fractions from “Noble” pomace inhibited MDA‐MB‐231 better than MCF‐7. But fraction 2 from “Cabernet Sauvignon” inhibited MCF‐7 better while fraction 1 and fraction 3 inhibited both 2 cells similarly. Moreover, the fractions from “Noble” pomace rather than “Cabernet Sauvignon” can inhibit MDA‐MB‐231 better. Finally, fractions from “Noble” pomace can induce S‐phase arrest and apoptosis on MDA‐MB‐231. These findings suggested the extracts from grape pomace especially those from “Noble,” are potential to be utilized as health beneficial products or even anti‐breast cancer agents.