Browsing by Subject "Tannins"
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Item Plant-Based Tannins as Antioxidants in Pre-Cooked Ground Beef Patties(2011-10-21) Cruzen, Shannon MichelleMeat lipid oxidation causes negative quality effects, especially in further processed products. Butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and rosemary extract (RM) are common antioxidants, but plant-based tannin compounds have been shown to be effective antioxidants. The objective was to evaluate antioxidant effectiveness, pH, color, and sensory effects of several tannin sources. In study 1, 19 percent fat ground beef was mixed with no treatment (control), BHA/BHT (0.02percent), RM (0.2percent), or 0.25percent or 0.5percent powders of Chardonnay grapeseed (CG), Norton grapeseed (NG), CitruSmart (CS), or dried cherry (CP). Raw and cooked patties were aerobically stored for 0 to 5 days at 4 degrees C. Cooked patties were analyzed using the TBARS (thiobarbituric acid reactive substances) method. Raw patties were analyzed for pH, instrumental color, subjective color, and ingredient specks. Study 2 was similar, except the treatments were 0.25percent and 0.5percent powders of CG, chestnut (CN), mimosa (M), and quebracho (Q) tannins, as well as 0.5percent NG, 0.02percent BHA/BHT, 0.2percent RM, and a control. In study 1, only the NG and CG pre-cooked patties had similar or lower TBARS values compared to RM and BHA/BHT patties. All tannin treatments, except 0.25percent CG and 0.25percent CS, lowered pH compared to the control. Patties with NG and 0.5percent CG were darker, and tannin-treated patties were not redder than the control. Patties with CG and 0.5percent NG were less yellow. Subjectively, tannin-treated patties did not have less discoloration during storage, and the CG and NG patties had numerous visible ingredient specks. In study 2, CN, M, Q, and 0.5percent CG treated patties had low TBARS during storage. pH was slightly lower in CG and CN patties than the control. All tannin-treated patties were darker than the control patties, except patties containing 0.25percent CG and Q, and control patties had the highest red values. Tannin-treatments patties, except CN and Q patties, were less yellow. Subjectively, only 0.25percent M patties had less discoloration than control patties, while 0.5percent CN patties were more discolored. Norton and Chardonnay grapeseed flour and chesnut, mimosa, and quebracho powders would be recommended for pre-cooked ground beef patties based on their antioxidant effectiveness in these studies.Item Post-harvest high heat treatment on grapes and the effects on wine quality relating compounds(2012-12) Zhang, Yanmei; Trela, Brent; Hellman, Edward W.; Mansouri, HosseinThis research evaluated simulated accumulated summer temperature conditions in grape shipping containers during transportation from vineyard to winery in Texas. Temperature treatments were applied to five batches of destemmed grapes comprised of three batches of red varieties and two batches of white varieties. After 0 to 15 hr treatments, the berries were processed and fermented to wines in micro scale. Phenolic constituents important to wine quality sensory perception, including total phenolics, anthocyanins, tannins and polymeric pigments, as well as color intensity, hue and standard wine parameters were quantified to evaluate the effects of heat at post-harvest stage on the subsequent wines. The results indicate that long distance transportation of berries in Texas may result in high phenolic extraction and elevated browning in white wines, while red wines tended to change red color intensity, tannin concentrations and red pigment profiles, which might not affect red wines sensorily. Heat treatment did not affect pH, titratable acidity, ethanol concentrations, browning, total phenolic concentrations or anthocyanin concentrations compared to the wines made from the low heat treated berries. The composition of phenolic constituents in red wines is relatively stable after the heat treatment before vinification.Item Sorghum Bran, Chestnut Wood Powder, and Chardonnay Grape Seed Flour Addition Effect on Lipid Oxidation and Color in Ground Beef Patties(2012-02-14) Roybal, Tabitha LynnNatural, plant-based tannin antioxidants are capable of inhibiting lipid oxidation in ground beef and may be possible alternatives to industry synthetic and natural standards of BHA/BHT and rosemary extract, respectively. Ground beef was purchased on three different days, each defining a batch during study 1. Treatments, added based on meat weight, included a control, 0.2 percent rosemary (RM), 0.02 percent BHA/BHT, 0.5 percent Chardonnay grape seed flour (CG), 0.1 percent and 0.25 percent chestnut wood flour (CN), and 0.25 percent and 0.5 percent of four sorghum bran varieties: black (BS), black with tannin (BTS), white (WS), and high tannin (TS). Patties, formed in duplicate, were randomly designated as cooked or raw and by 0 to 5 day storage, and were aerobically stored at 4 degrees C. Cooked patties were analyzed using the TBARS method. Raw patties were analyzed for subjective and objective color, number of ingredient specks, and pH. In study 2, six treatments were chosen for sensory evaluation including a control, 0.2 percent RM, 0.02 percent BHA/BHT, 0.5 percent CG, 0.1 percent CN, and 0.5 percent BTS. Preparation, and raw and cooked analysis occurred similar to study 1. Additional patties were made for day 1 consumption by consumer panelists. In study 1, all treatments except 0.25 percent WS reduced TBARS values over time compared to 0.2 percent RM. Four treatments (0.5 percent BTS, 0.5 percent CG, 0.25 percent CN, and 0.1 percent CN) showed no significant increase in TBARS values over storage. BS and BTS yielded the lowest color space values (CIE L*, a*, and b*; P<0.0001). Ingredient specks were possible color measurement influences. In both studies antioxidant addition reduced TBARS values over time compared to the control (P<0.0001), and percent discoloration was highest in patties containing a sorghum treatment (P<0.0001). Patties containing 0.1 percent CN were significantly favored in terms of overall like (P<0.0002) and flavor like (P<0.0001). Patties containing 0.2 percent RM were ranked lowest in overall and flavor like, and ground beef-like bite. Patties containing 0.5 perent CG were least liked according to tenderness level (P<0.005). These results indicate that CG, CN, and certain varieties of sorghum bran can be added to pre-cooked ground beef products and provide better antioxidant protection than currently used ingredients of BHA/BHT and rosemary extract.