Emmanuel Kwaw

Effects of Ultrasound, High Pressure, and Manosonication Processes on Phenolic Profile and Antioxidant Properties of a Sulfur Dioxide-Free Mulberry (Morus nigra) Wine

The present investigation aimed to evaluate the effects of ultrasound, high pressure, and manosonication on phenolic profile in correlation to antioxidant properties of aged mulberry wines (AMWs). The results indicated a positive effect of non-thermal processes on total phenol content of the AMW conversely to total anthocyanin content, which was negatively affected by pressurization and manosonication. With regard to total flavonoid content, sonication was found to exert a positive effect. A similar trend was also observed for each of the 18 phenolic compounds quantified. The outcome suggests that these phenolic compounds have potent antioxidant properties. From correlation analysis, phenolic acids were noted to be responsible for 1,1-diphenyl-2-picrylhydrazyl, N,N-dimethyl-p-phenylenediamine, and hydrogen peroxide capacities, while total antioxidant, ferric reducing antioxidant power, reducing power, cupric ion, metal chelating, lipid peroxidation, superoxide anion, 2,2′-azino-bis(3-ethylbenzothiazolin-6-sulfonic acid), nitric oxide, and hydroxyl radical capacities were attributed to flavonols and anthocyanins.

Aroma profile and sensory characteristics of a sulfur dioxide-free mulberry (Morus nigra) wine subjected to non-thermal accelerating aging techniques

The present study was undertaken to assess accelerating aging effects of high pressure, ultrasound and manosonication on the aromatic profile and sensorial attributes of aged mulberry wines (AMW). A total of 166 volatile compounds were found amongst the AMW. The outcomes of the investigation were presented by means of geometric mean (GM), cluster analysis (CA), principal component analysis (PCA), partial least squares regressions (PLSR) and principal component regression (PCR). GM highlighted 24 organoleptic attributes responsible for the sensorial profile of the AMW. Moreover, CA revealed that the volatile composition of the non-thermal accelerated aged wines differs from that of the conventional aged wines. Besides, PCA discriminated the AMW on the basis of their main sensorial characteristics. Furthermore, PLSR identified 75 aroma compounds which were mainly responsible for the olfactory notes of the AMW. Finally, the overall quality of the AMW was noted to be better predicted by PLSR than PCR.

Impact of extraction parameters and their optimization on the nutraceuticals and antioxidant properties of aqueous extract mulberry leaf

ABSTRACT An investigation into the efficient use of water as a solvent and the influence of extraction temperature, extraction time, water to leaf powder ratio, particle size, and extraction cycle on the nutraceutical and antioxidant profile of aqueous mulberry leaf extract were conducted using a single-factor experiment approach. All the assessed extracting parameters showed a significant effect on the nutraceutical compounds and antioxidant properties. The optimum extraction conditions were as follows: extraction temperature of 70°C, extraction time of 40 min, water to leaf powder ratio of 40:1 ml/g, particle size of 25 µm, and two extraction cycles. Based on these optimal conditions, chlorogenic acid (62.10 mg/g), caffeic acid (32.21 mg/g), kaempferol-7-O-glucoside (19.30 mg/g), quercetin-3-rutinose (15.69 mg/g), quercetin-3-O-glucoside (32.38 mg/g), kaempferol-3-(6-rhamnosylglucoside) (42.52 mg/g), quercetin-3-(6-malonylglucoside) (65.19 mg/g), kaempferol-3-glucoside (66.27 mg/g), kaempferol-3-(6-malonylglucoside) (50.18 mg/g), 1-deoxynojirimycin (15.58 mg/g), and gamma-aminobutyric acid (5.05 mg/g) were obtained. The optimal aqueous extract had high antioxidant properties of 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (39.98 mM/g), cupric ion reducing capacity (58.93 mM/g), 1,1-diphenyl-2-picrylhydrazyl (101.33 mM/g), and ferric reducing antioxidant power capacity (233.77 mM/g) of dried mulberry leaf extract.

Proteomics profile of Hanseniaspora uvarum enhanced with trehalose involved in the biocontrol efficacy of grape berry

This present study tested the extent to which 2% w/v trehalose enhanced the proteins expression profile of Hanseniaspora uvarum Y3. Furthermore, it explored the relative gene expression of stilbene synthase (StSy), one of the vital defense-related genes found in the skin of grapes. The proteomics profile revealed that 29 proteins were differentially expressed out of which 26 were significantly up-regulated and 3 were download-regulated. The pathogenesis related (PR) and other protein spots were visible at 97.4 kDa and 14.4 kDa. Peroxiredoxin TSA1 and superoxide dismutase were the main proteins involved in defense response and both proteins were significantly up-regulated. The carbohydrate and energy metabolism proteins were also significantly up-regulated. The results revealed that the treatments were associated with substantial increase in peroxidase activity compared to the control. StSy relative gene expression level was observed to increase by 2.5-fold in grapes treated with the pre-enhanced H. uvarum compared to the control.

Effect of pulsed light treatment on the phytochemical, volatile, and sensorial attributes of lactic-acid-fermented mulberry juice

ABSTRACT Lactic-acid-fermented mulberry juice (LFMJ) was subjected to pulsed light (PL) treatment at exposure time of 2, 4, and 8 s at high insensitive pulses of 14.0 J/cm2. The effect of PL treatment on the microbial inactivation, physicochemical, phytochemical, volatile, and sensory characteristics of LFMJ was evaluated. It was found that the PL was able to reduce the microbial load to acceptable levels (1.02 ± 0.04 log10 cfu/mL) with no significant impact on the physicochemical properties of LFMJ. It was also observed that the PL treatment caused a slight decrease in anthocyanin concentration at 8 s exposure time. The color difference (∆E) of the juice treated for 2 and 4 s fell below the slightly noticeable range 0.5<ΔE<1.5 while ∆E values for the 8 s (0.55 ± 0.02) and the thermal (0.50 ± 0.02) treated samples were slightly noticeable. The volatile profile and odor activity values were positively affected by increasing the exposure time. The results depict that, under the present experimental conditions, the application of the PL resulted in a fermented juice with superior quality attributes as compared to the thermal treated juice.

Utilization of composite flours as breading agents for deep frying of chicken breast

The present study evaluated different single and composite flours from wheat, millet, sorghum and soybean as breading agents in deep frying of chicken breast. The proximate composition of the breading agents was assessed. The effects of the breading agents were established by assessing the percentage adhesiveness of the flours, yield, frying losses and texture. Sensory test was also carried out on a nine-point hedonic scale to assess the color, taste, moistness, texture, aroma and overall sensory acceptability. Significant differences (p < 0.05) were observed among the breading agents in terms of their proximate compositions. There were significant differences in the percentage adhesiveness, percentage yield, frying losses and hardness among the breaded chicken. Significant difference (p < 0.05) was observed on the effect of the breading agents on the proximate compositions of the fried breaded chicken breast. There was an increase in fat absorption in the single cereal coated samples compared to the composite flours. The chicken breast coated with equal ratio of soybean and sorghum composite flour was the most preferred with overall acceptability of 84.44%. Our results indicated that, the use of equal ratio of sorghum and soy bean flour was the best breading agent.

The use of lactic acid bacteria as starter culture and its effect on the proximate composition and sensory acceptability of millet beverage

Majority of traditional cereal-based foods consumed in Africa are mostly processed by spontaneous fermentation. In Ghana, pearl millet (Pennisetum glaucum) is used for the production of fermented foods such as tuo zaafi, koko, furo-furo, masa, and fura. This study investigated some dominant lactic acid bacteria (L. brevis (S1), L. plantarum (S2), L. fermentum (S3) and L. paracasei (S4) used as starter cultures in the fermentation of millet beverage. The study further assessed the effects of the individual strains on the proximate composition and sensory characteristics of the millet beverages. The results indicate that the proximate compositions of the fermented beverages (S1, S2, S3 and S4) were significant different (p<0.05) from the unfermented beverage (UF) with the exception of moisture and fat. It was also observed that, there was significant (p<0.05) increase in protein contents in the fermented beverages with S2 having the highest % protein. The high protein content of the fermented beverages (S1, S2, S3 and S4) compared to the UF would be due to an increase in proteolytic actions during the fermentation which might have resulted in the production of essential amino acids and other simple protein compounds. With regards to the organic acids composition, the most dominant acid was the lactic acid with S2 having the highest (4.81g/l). The sensory analysis revealed that the S1 fermented millet beverage was the most preferred followed by S2. The differences in sensorial properties were significantly (p<0.05) associated with the kind of lactic acid bacteria used in the fermentation. Furthermore, the results showed that millet beverage with good color, taste and aroma was preferred. In general, S1, S2. S3 and S4 were all significantly different from UF due to the fact that fermentation is important for improving product sensory attributes and safety by reduction of toxic cyanogenic glucosides.