Grape seed powders, byproducts of either winemaking or grape processing, were prepared from
Vitis vinifera (Merlot and Chardonnay) and
Vitis rotundifolia (Muscadine) species. Water, methanol, acetone ...and ethanol were tested as extractants on Muscadine seed powder. Antioxidant activities of grape seeds and skins were determined as oxygen radical absorbance capacity with phycoerythrin (ORAC
PE) for both grape species. The results indicated that aqueous solutions of ethanol, methanol or acetone were better than a single-compound solvent system for extraction of total phenols from Muscadine seed powder. Antioxidant capacities of Chardonnay, Merlot and Muscadine grape seeds were 638, 345 and 311
μmol Trolox equivalent (TE)/g dry weight in decreasing order
(
P
<
0.05
)
, respectively. (ORAC
PE) values of Chardonnay and Merlot grape skin powders were similar. Total phenol contents of extracts used to determine the antioxidant capacities of grape seeds and skins had a trend similar to (ORAC
PE) values. Our results showed that health functional components of grape skin and seed powders from the tested byproducts of grape/wine industry are comparable to those of fruits and vegetables.
Mild heat treatment of carrot slices as a pre-treatment for frozen storage was accomplished by exposure of slices to radiant heat to maximise thermal exposure of the cells at the surface while ...preserving the integrity of cells within the slices. Cell damage as a consequence of this treatment on texture was evaluated. Carrot slices treated for 7 s with radiant energy in the far-infrared region from a radiant surface at 810 K were evaluated for cell damage by relative electrolyte leakage and microscopic observations. Cell damage caused by heating in boiling water from 5 to 30 s was used for comparison. Carrot slices heated by far-infrared radiation contained damaged cells only in the first half millimetre from the surface and exhibited the texture characteristic of the raw tissue.
Grape seeds and skins are good sources of phytochemicals such as gallic acid, catechin, and epicatechin and are suitable raw materials for the production of antioxidative dietary supplements. The ...differences in levels of the major monomeric flavanols and phenolic acids in seeds and skins from grapes of Vitis vinifera varieties Merlot and Chardonnay and in seeds from grapes of Vitis rotundifolia variety Muscadine were determined, and the antioxidant activities of these components were assessed. The contribution of the major monomeric flavonols and phenolic acid to the total antioxidant capacity of grape seeds and skins was also determined. Gallic acid, monomeric catechin, and epicatechin concentrations were 99, 12, and 96 mg/100 g of dry matter (dm) in Muscadine seeds, 15, 358, and 421 mg/100 g of dm in Chardonnay seeds, and 10, 127, and 115 mg/100 g of dm in Merlot seeds, respectively. Concentrations of these three compounds were lower in winery byproduct grape skins than in seeds. These three major phenolic constituents of grape seeds contributed <26% to the antioxidant capacity measured as ORAC on the basis of the corrected concentrations of gallic acid, catechin, and epicatechin in grape byproducts. Peroxyl radical scavenging activities of phenolics present in grape seeds or skins in decreasing order were resveratrol > catechin > epicatechin = gallocatechin > gallic acid = ellagic acid. The results indicated that dimeric, trimeric, oligomeric, or polymeric procyanidins account for most of the superior antioxidant capacity of grape seeds. Keywords: Antioxidant; antioxidant capacity; catechin; Chardonnay; epicatechin; gallic acid; galvinoxyl; grape seed; grape skin; Merlot; Muscadine; ORAC
The thermal resistance of Clostridium sporogenes PA 3679 ATCC 7955 was determined in soymilk (pH 7) and 0.1% peptone water (pH 7) by the capillary tube method. In the continuous flow high-pressure ...throttling, the temperature of soymilk increased due to instantaneous pressure release and the additional heat was supplied by a heat exchanger to achieve the set temperature. The soymilk was immediately cooled after a short preset hold time to below 40 °C. A significant increase in the heat resistance was observed in C. sporogenes spores when heated in soymilk in comparison to 0.1% peptone water. The D₁₂₁-value for spores in soymilk was approximately 3-folds higher than peptone water. The z-value was also much higher in soymilk as compared to that in 0.1% peptone water. Continuous flow high-pressure throttling (HPT) from 207 or 276 MPa to atmospheric pressure reduced the microbial populations in inoculated soymilk up to 6 log cycles when the holding times were 10.4, 15.6, and 20.8 s and the process temperatures were 85, 121, 133, and 145 °C, respectively. The sporicidal effect increased as the operating pressure, time, and temperature were increased. More injured spores were found at 207 MPa than at 276 MPa, indicating that lower pressure caused cell injury whereas high pressure caused cell death.
The minimum inhibitory concentrations (MIC) of 9 liquid smoke fractions against pathogenic and food spoilage organisms were determined using broth or agar dilution methods. Extract F1 (highest ...carbonyl content and lowest pH) was most effective against all microorganisms. MIC of F1 was 0.75% against Lactobacillus plantarum; 1.5% against Listeria innocua M1, Salmonella, Escherichia coli 8677, Saccharomyces cerevisiae, and Aspergillus niger; and 2% against Pseudomonas putida. The least effective smoke fraction F9 had MIC >9% against most organisms tested, had high pH, low phenols, and low carbonyls. Growth curves of individual bacteria and yeast below the MIC exhibited a prolonged lag phase that increased with increasing smoke concentrations.
Soymilk was prepared from boiled and unboiled comminuted suspensions of dehulled soybean and water using pressurized homogenization (one pass and two pass). Particle size showed significant ...differences between soymilks homogenized by one pass and two pass. Apparent viscosities and total solid contents showed significant differences between boiled and unboiled treatments. Soymilks exhibited pseudoplastic and thixotropic behavior and Arrhenius model was fitted to express temperature dependence of apparent viscosity. Microscopic images showed hydrated, separated, uniformly distributed, and homogeneous particles in boiled two-pass soymilk as they were disrupted easily and it was selected as the best treatment for processing soymilk containing all of the soybean solids.
Functional ingredients of grape seeds include several flavonoids with a phenolic nature such as monomeric flavanols (catechin and epicatechin), dimeric, trimeric and polymeric procyanidins, and ...phenolic acids (gallic acid and ellagic acid). These flavonoids have been reported to exhibit antioxidant activity
in vivo and
in vitro in a number of studies. The antioxidant activity of flavonoids is closely associated with activity against various cancer types, cardiovascular diseases and several dermal disorders. In this study, we present a review of functional components of grape seeds or skins with emphasis on health benefits of their use in the human diet.
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