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Gary Williamson - One of the best experts on this subject based on the ideXlab platform.

  • hibiscus sabdariffa roselle extracts and wine phytochemical profile physicochemical properties and carbohydrase inhibition
    Journal of Agricultural and Food Chemistry, 2016
    Co-Authors: Idolo Ifie, Lisa J Marshall, Peter Ho, Gary Williamson
    Abstract:

    Three varieties of Hibiscus sabdariffa were analyzed for their phytochemical content and inhibitory potential on carbohydrate-digesting enzymes as a basis for selecting a variety for wine production. The dark red variety was chosen as it was highest in phenolic content and an aqueous extract partially inhibited α-glucosidase (maltase), with delphinidin 3-O-sambubioside, cyanidin 3-O-sambubioside, and 3-O-caffeoylquinic acid accounting for 65% of this activity. None of the varieties significantly inhibited α-amylase. Regarding Hibiscus sabdariffa wine, the effect of Fermentation Temperature (20 and 30 °C) on the physicochemical, phytochemical, and aroma composition was monitored over 40 days. The main change in phytochemical composition observed was the hydrolysis of 3-O-caffeolquinic acid and the concomitant increase of caffeic acid irrespective of Fermentation Temperature. Wine fermented at 20 °C was slightly more active for α-glucosidase inhibition with more fruity aromas (ethyl octanoate), but there we...

  • hibiscus sabdariffa roselle extracts and wine phytochemical profile physicochemical properties and carbohydrase inhibition
    Journal of Agricultural and Food Chemistry, 2016
    Co-Authors: Idolo Ifie, Lisa J Marshall, Gary Williamson
    Abstract:

    Three varieties of Hibiscus sabdariffa were analyzed for their phytochemical content and inhibitory potential on carbohydrate-digesting enzymes as a basis for selecting a variety for wine production. The dark red variety was chosen as it was highest in phenolic content and an aqueous extract partially inhibited α-glucosidase (maltase), with delphinidin 3-O-sambubioside, cyanidin 3-O-sambubioside, and 3-O-caffeoylquinic acid accounting for 65% of this activity. None of the varieties significantly inhibited α-amylase. Regarding Hibiscus sabdariffa wine, the effect of Fermentation Temperature (20 and 30 °C) on the physicochemical, phytochemical, and aroma composition was monitored over 40 days. The main change in phytochemical composition observed was the hydrolysis of 3-O-caffeolquinic acid and the concomitant increase of caffeic acid irrespective of Fermentation Temperature. Wine fermented at 20 °C was slightly more active for α-glucosidase inhibition with more fruity aromas (ethyl octanoate), but there were more flowery notes (2-phenylethanol) at 30 °C.

Idolo Ifie - One of the best experts on this subject based on the ideXlab platform.

  • hibiscus sabdariffa roselle extracts and wine phytochemical profile physicochemical properties and carbohydrase inhibition
    Journal of Agricultural and Food Chemistry, 2016
    Co-Authors: Idolo Ifie, Lisa J Marshall, Peter Ho, Gary Williamson
    Abstract:

    Three varieties of Hibiscus sabdariffa were analyzed for their phytochemical content and inhibitory potential on carbohydrate-digesting enzymes as a basis for selecting a variety for wine production. The dark red variety was chosen as it was highest in phenolic content and an aqueous extract partially inhibited α-glucosidase (maltase), with delphinidin 3-O-sambubioside, cyanidin 3-O-sambubioside, and 3-O-caffeoylquinic acid accounting for 65% of this activity. None of the varieties significantly inhibited α-amylase. Regarding Hibiscus sabdariffa wine, the effect of Fermentation Temperature (20 and 30 °C) on the physicochemical, phytochemical, and aroma composition was monitored over 40 days. The main change in phytochemical composition observed was the hydrolysis of 3-O-caffeolquinic acid and the concomitant increase of caffeic acid irrespective of Fermentation Temperature. Wine fermented at 20 °C was slightly more active for α-glucosidase inhibition with more fruity aromas (ethyl octanoate), but there we...

  • hibiscus sabdariffa roselle extracts and wine phytochemical profile physicochemical properties and carbohydrase inhibition
    Journal of Agricultural and Food Chemistry, 2016
    Co-Authors: Idolo Ifie, Lisa J Marshall, Gary Williamson
    Abstract:

    Three varieties of Hibiscus sabdariffa were analyzed for their phytochemical content and inhibitory potential on carbohydrate-digesting enzymes as a basis for selecting a variety for wine production. The dark red variety was chosen as it was highest in phenolic content and an aqueous extract partially inhibited α-glucosidase (maltase), with delphinidin 3-O-sambubioside, cyanidin 3-O-sambubioside, and 3-O-caffeoylquinic acid accounting for 65% of this activity. None of the varieties significantly inhibited α-amylase. Regarding Hibiscus sabdariffa wine, the effect of Fermentation Temperature (20 and 30 °C) on the physicochemical, phytochemical, and aroma composition was monitored over 40 days. The main change in phytochemical composition observed was the hydrolysis of 3-O-caffeolquinic acid and the concomitant increase of caffeic acid irrespective of Fermentation Temperature. Wine fermented at 20 °C was slightly more active for α-glucosidase inhibition with more fruity aromas (ethyl octanoate), but there were more flowery notes (2-phenylethanol) at 30 °C.

N. Tzanetakis - One of the best experts on this subject based on the ideXlab platform.

  • structure development and acidification kinetics in fermented milk containing oat β glucan a yogurt culture and a probiotic strain
    Food Hydrocolloids, 2014
    Co-Authors: Athina Lazaridou, Costas G Biliaderis, Amalia Serafeimidou, Thomas Moschakis, N. Tzanetakis
    Abstract:

    The impact of oat β-glucan fortification (1.4%) on the acidification and gelation kinetics of fermented skimmed milk (12% total solids) as well as the effects of inclusion of a probiotic strain (Lactobacillus paracasei subsp. paracasei B117) into the yogurt starter culture (Lactobacillus delbrueckii subsp. bulgaricus Y 6.15 and Streptococcus thermophilus Y 4.10) and Fermentation Temperature (36, 38 and 40 °C) have been explored by dynamic rheometry, pH measurements and microbial enumeration. The viability/growth of the mixed culture bacteria was also evaluated upon storage. Incorporation of β-glucan to milk resulted in phase separation between proteins and the added polysaccharide, altering the entire gelation process as manifested by the development of a transient gel structure at the early stages, followed by significant (P   1) at the end of Fermentation (pH = 4.6) when performed at 36 °C. A higher Fermentation Temperature accelerated the acidification kinetics, yielding a shorter gelation time, but the storage modulus values of milk gels decreased. Inclusion of the probiotic strain into the yogurt starter culture seemed to increase the gelation rate without affecting the gelation time and gel strength. Viability of all three culture bacteria was enhanced by decreasing Fermentation Temperature and during storage. Moreover, the L. paracasei showed good compatibility with the yogurt starter culture and the addition of β-glucan enhanced the viability of the probiotic strain in the fermented products throughout cold storage (4 °C).

  • modelling of the acidification process and rheological properties of milk fermented with a yogurt starter culture using response surface methodology
    Food Chemistry, 2003
    Co-Authors: E Kristo, Costas G Biliaderis, N. Tzanetakis
    Abstract:

    Abstract The simultaneous effects of Fermentation Temperature (FT, 36.7–43.4 °C), milk total solid level (TS, 11.3–14.7%, w/v) and total inoculum concentration (TI, 1.66–3.34 v/v) on the acidication process and the rheological properties of milk Fermentation with Lactobacillus delbrueckii ssp bulgaricus Y 6.15 and Streptococcus thermophilus Y 4.10 were explored by the means of response surface methodology. Maximum storage modulus ( G ′ max ), minimum loss tangent (tan δ min ), rate of gelation ( I E ) and onset of gelation were the rheological parameters studied, whereas maximum acidification rate ( V m ), time at which maximum acidification rate was observed ( T m ) and time to reach the end of Fermentation ( T e ) characterized the kinetics of acidification during milk Fermentation. TS strongly affected G ′ max and tan δ min ; high TS resulted in a large increase in G ′ max and decrease in tan δ min . Increasing Fermentation Temperature gave a decrease in the onset of gelation, in T m and T e , and increase in the rate of gelation ( I E ). V m was mainly affected by the interaction TS×FT. Under conditions of relatively low FT (37–39 °C), high TS (around 14%) and high TI (3–3.5%), the gelation and acidification rates were at medium levels and Fermentation took a longer time to finish, but the formed gels were firmer, showing higher G ′ max and lower tan δ min values. Under all conditions examined, a high number of viable lactic acid bacteria in the final product was detected during storage (21 days, 4 °C) for both microorganisms used in the starter culture.

  • modelling of rheological microbiological and acidification properties of a fermented milk product containing a probiotic strain of lactobacillus paracasei
    International Dairy Journal, 2003
    Co-Authors: E Kristo, Costas G Biliaderis, N. Tzanetakis
    Abstract:

    Abstract The simultaneous effect of Fermentation Temperature (FT, 36.7–43.4°C), milk total solid level (TS, 11.3–14.7%, w/v) and total inoculum concentration (TI, 2.16–3.84 v/v) on the acidification process and the rheological properties of fermented milk products with Lactobacillus paracasei ssp paracasei B117, Lactobacillus delbrueckii ssp bulgaricus Y 6.15 and Streptococcus thermophilus Y 4.10 was explored by means of response surface methodology. Maximum storage modulus (G′max), minimum loss tangent (tan δmin), rate of gelation (IE) and onset of gelation were the rheological parameters studied. Maximum acidification rate (Vm), time at which maximum acidification rate was observed (Tm), and time to reach the end of Fermentation (Te) characterized the kinetics of acidification, whereas the increase in the number of the three bacteria at the end of Fermentation was chosen as the microbiological parameter of the system. The growth/survival of microorganisms and the organic acid profile during cold storage as well as the overall product acceptability by a consumer panel were also assessed. TS strongly affected G′max and tan δmin; high TS resulted in large increase in G′max and decrease in tan δmin. Increasing Fermentation Temperature gave a decrease in the onset of gelation, Vm, Tm and Te, and an increase in the gelation rate (IE). Under conditions of relatively low FT (37–40°C), high TS (about 14%) and high TI (3–4%), relatively high gelation and low acidification rates were observed, Fermentation took a longer time to finish, but the formed gels were firmer, showing higher G′max and lower tan δmin values. Low FT (36–38°C) enabled higher increase in the number of L. paracasei B 117. The probiotic strain showed good compatibility with the S. thermophilus Y 4.10 and L. bulgaricus Y 6.15, and satisfactory levels of all bacteria were found during Fermentation and storage at 4°C for 21 days. No major differences in lactic and uric acid contents were seen between the control (probiotic strain-free product) and the probiotic fermented milk, whereas the latter contained slightly higher amounts of citric, pyruvic and orotic acids. Moreover, the probiotic fermented milk was graded by the consumer panel with a similar acceptability score as the control product.

Lisa J Marshall - One of the best experts on this subject based on the ideXlab platform.

  • hibiscus sabdariffa roselle extracts and wine phytochemical profile physicochemical properties and carbohydrase inhibition
    Journal of Agricultural and Food Chemistry, 2016
    Co-Authors: Idolo Ifie, Lisa J Marshall, Peter Ho, Gary Williamson
    Abstract:

    Three varieties of Hibiscus sabdariffa were analyzed for their phytochemical content and inhibitory potential on carbohydrate-digesting enzymes as a basis for selecting a variety for wine production. The dark red variety was chosen as it was highest in phenolic content and an aqueous extract partially inhibited α-glucosidase (maltase), with delphinidin 3-O-sambubioside, cyanidin 3-O-sambubioside, and 3-O-caffeoylquinic acid accounting for 65% of this activity. None of the varieties significantly inhibited α-amylase. Regarding Hibiscus sabdariffa wine, the effect of Fermentation Temperature (20 and 30 °C) on the physicochemical, phytochemical, and aroma composition was monitored over 40 days. The main change in phytochemical composition observed was the hydrolysis of 3-O-caffeolquinic acid and the concomitant increase of caffeic acid irrespective of Fermentation Temperature. Wine fermented at 20 °C was slightly more active for α-glucosidase inhibition with more fruity aromas (ethyl octanoate), but there we...

  • hibiscus sabdariffa roselle extracts and wine phytochemical profile physicochemical properties and carbohydrase inhibition
    Journal of Agricultural and Food Chemistry, 2016
    Co-Authors: Idolo Ifie, Lisa J Marshall, Gary Williamson
    Abstract:

    Three varieties of Hibiscus sabdariffa were analyzed for their phytochemical content and inhibitory potential on carbohydrate-digesting enzymes as a basis for selecting a variety for wine production. The dark red variety was chosen as it was highest in phenolic content and an aqueous extract partially inhibited α-glucosidase (maltase), with delphinidin 3-O-sambubioside, cyanidin 3-O-sambubioside, and 3-O-caffeoylquinic acid accounting for 65% of this activity. None of the varieties significantly inhibited α-amylase. Regarding Hibiscus sabdariffa wine, the effect of Fermentation Temperature (20 and 30 °C) on the physicochemical, phytochemical, and aroma composition was monitored over 40 days. The main change in phytochemical composition observed was the hydrolysis of 3-O-caffeolquinic acid and the concomitant increase of caffeic acid irrespective of Fermentation Temperature. Wine fermented at 20 °C was slightly more active for α-glucosidase inhibition with more fruity aromas (ethyl octanoate), but there were more flowery notes (2-phenylethanol) at 30 °C.

Aijie Wang - One of the best experts on this subject based on the ideXlab platform.

  • fermentative hydrogen production from corn stover hydrolyzate by two typical seed sludges effect of Temperature
    International Journal of Hydrogen Energy, 2015
    Co-Authors: Kun Zhang, Nanqi Ren, Aijie Wang
    Abstract:

    Abstract The Temperature effect on fermentative hydrogen (H 2 ) production from corn stover hydrolyzate was investigated under mesophilic (37 and 30 °C), thermophilic (55 °C), and extreme thermophilic (70 °C) conditions by using two typical seed sludges (activated sludge and anaerobic granular sludge). Among various Temperatures, the Fermentation at 55 °C reached the optimal H 2 production with the values of 6.08 mmol-H 2 /g-utilized sugar for activated sludge and 7.74 mmol-H 2 /g-utilized sugar for anaerobic granular sludge, respectively. For the two seed sludges, the effectiveness of Fermentation Temperature on H 2 production both followed the order as 55 °C > 70 °C > 37 °C ≈ 30 °C. The soluble metabolites composition at 55 °C showed the highest acetate and butyrate concentrations, as well as the minimum ethanol production, coinciding with better H 2 -producing performances in these cases. Microbial community analysis indicated that microbial community diversity significantly decreased with increased Fermentation Temperature. Facultative anaerobes, such as Enterobacter spp., Klebsiella spp., and Citrobacter spp., were dominant in microbial community of the two seed sludges. As efficient H 2 producers, Bacillus sp. AB5283 in activated sludge and Thermoanaerobacterium sp. PO-2009 in anaerobic granular sludge might be mainly responsible for high H 2 yields under thermophilic condition.