Browsing by Subject "antioxidants"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
Item Effects of dietary fat and fiber on the oxidative status of the small intestine and colon of rats(Texas A&M University, 2006-08-16) Sanders, Lisa MerleColon cancer is one of the most commonly diagnosed cancers in the US, yet small intestine cancer is a rare event. While there are many similarities between these two tissues, inherent differences such as redox status, may contribute to the variation in cancer occurrence. We examined the difference in reactive oxygen species (ROS) generation, antioxidant enzyme activity and oxidative DNA damage in the small and large intestine of rats under normal conditions and following exposure to exogenous oxidative stress. Basal ROS and antioxidant enzyme activities were greater in the colon than the small intestine, and the balance of ROS to antioxidant enzymes in the colon was more pro-oxidant than in the small intestine. During oxidative stress, ROS and oxidative DNA damage were greater in the colon than the small intestine. Thus the colon responds to oxidative stress less effectively than the small intestine, possibly contributing to increased cancer incidence at this site. We next wanted to understand how diets containing a combination of fish or corn oil and pectin or cellulose may alter the redox environment of the colon. ROS, oxidative DNA damage, antioxidant enzyme activity and apoptosis were measured in colonocytes of rats fed one of four diets containing either corn oil or fish oil and cellulose or pectin. Measurements were madein rats untreated with carcinogen and rats exposed to a chemical carcinogen and radiation. In rats not treated with a carcinogen, fish oil enhanced ROS, and fish oil/pectin suppressed antioxidant enzymes as compared to corn oil/cellulose. Oxidative DNA damage was inversely related to ROS in the fish oil/pectin diet and apoptosis was enhanced relative to other diets. In carcinogen treated and irradiated rats, a similar protective effect was seen with fish oil/pectin as evidenced by a reduction in oxidative DNA damage and enhancement of apoptosis. This suggests that a diet containing fish oil/pectin may protect against colon carcinogenesis by modulation of the redox environment to promote apoptosis and minimize oxidative DNA damage.Item Factors Influencing the Stability and Marketability of a Novel, Phytochemical-Rich Oil from the A?ai Palm Fruit (Euterpe oleracea Mart.)(2012-02-14) Duncan, Christopher EdwardThe a?ai palm fruit has recently become the focus of numerous research endeavors due to its extraordinary antioxidant content. However, little is known about the fruit?s phytochemical rich oil, which is a by-product of the a?ai pulp. Therefore, the aim of this study was to investigate the phytochemical content of a?ai oil and its relation to oxidative stability. A total of 206 mg/kg of chlorophylls, which included chlorophyll a as well as four chlorophyll derivatives were tentatively identified by HPLC in crude a?ai oil (CAO). Two predominant carotenoids (216 mg/kg ?-carotene and 177 mg/kg lutein) were also characterized in addition to ?-tocopherol (645 mg/kg). Initial investigations into oil stability focused upon the photooxidation of a?ai oil due to its significant chlorophyll content and findings demonstrated that the increases of nonanal were observed when phospholipids and polyphenolics were reduced. Subsequently, investigations into the interactions between phospholipids and lipophilic antioxidants and their contributions to the stability of a?ai oil were also assessed by isolating phytochemicals and selectively reconstituting the oil. Findings demonstrated a potential relationship between phospholipids and lipophilic antioxidants, but this was not conclusive. Advances in the processing of the a?ai pulp by-product created from the clarification process yielded a partially refined a?ai oil (RAO). The stability of both RAO and CAO as a result of autoxidation were compared to other common food oils (olive, canola, and soybean) and primary and secondary oxidation data suggested CAO was most stable. The difference in the stability of the two a?ai oils was also investigated by blending these oils and assessing oxidation. An increased stability was demonstrated in the blended RAO, which suggested a significant antioxidant contribution from the CAO. With such similar lipophilic compositions in CAO and RAO, it is theorized that the driving factor behind the stability of CAO can be attributed to its water soluble antioxidant content. While further investigations are required to fully comprehend the interactions of a?ai oil phytochemicals, these experiments provide insight into the phytochemical content and stability of a?ai oil. The understanding and information obtained in these studies is geared at increasing the marketability of a?ai oil as a food ingredient.Item Nutraceutical tortillas and tortilla chips prepared with bran from specialty sorghums(Texas A&M University, 2007-04-25) Cedillo Sebastian, GuisselleThe effects of sorghum bran addition on table tortillas and tortilla chip properties were evaluated. Texture, phenol content, antioxidant activity, and sensory characteristics were evaluated. Texture was measured by objective and subjective tests. Products were analyzed for phenols following the Folin-Ciocalteu procedure and for antioxidant potential following the ABTS (2,2'-azinobis (3- ethylbenzothiazoline-6-sulfonic acid) method. Sensory properties were evaluated using a nine point hedonic scale. Bran from two specialty sorghums: sumac (high tannin) and black (high anthocyanins) was added at 0, 5, and 10% to table tortillas and tortilla chips. For table tortillas the interaction of sorghum bran with an antistaling formula containing guar gum, carboxymethylcellulose and maltogenic alpha-amylase was assessed. Tortillas containing sorghum bran had a more friable structure than the control. This detrimental effect was overcome by the antistaling formula. Additives made fluffier tortillas with improved texture and appearance. Tortillas containing sorghum bran and the antistaling formula were acceptable to panelists. At 5% sorghum bran inclusion, there was no significant difference in sensory attributes from the control aside from appearance. Tortillas containing sorghum bran had a dark natural color comparable to that of blue corn tortillas. Tortilla chip texture was not significantly affected by addition of bran to the formula. As in table tortillas, addition of sorghum bran produced minor changes in the texture and flavor of the product, but a significant change in appearance acceptability. Tortilla chips had a dark color, comparable to the one of blue corn tortilla chips. Sumac bran yielded larger amounts of phenols and antioxidant activity than black bran. Levels of phenols and antioxidant potential increased with increased bran. Although processing caused a measurable loss of sorghum bran antioxidants, table tortilla and tortilla chips were still a significant source of phenols and antioxidant activity. The addition of sorghum bran produced tortillas and tortilla chips with increased levels of dietary fiber and antioxidants, without adversely affecting other sensory properties.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 Screening potato genotypes for antioxidant activity, identification of the responsible compounds, and differentiating Russet Norkotah strains using AFLP and microsatellite marker analysis(Texas A&M University, 2005-02-17) Hale, Anna LouiseTotal antioxidant activity and total carotenoid levels were evaluated for more than 100 common potato (Solanum tuberosum, L.) cultivars grown in the United States, advanced breeding lines from several Western U.S. breeding programs, and 47 related, tuber-bearing species. An initial assessment of variability for antioxidant activity provided baseline information to be used for potential potato promotion and for the development of new varieties with greater human health benefits. Wide variability in antioxidant levels provided evidence of genetic control of this trait, indicating that it could be possible to breed for enhanced levels of antioxidant compounds in potato. Accessions, varieties, and advanced breeding lines identified in the broad screen as having high antioxidant activity and high total carotenoid levels, were fine screened via HPLC to determine specific phenolic and carotenoid compounds present in potato. The objective of the study was to identify parents for use in the Texas breeding program to develop potato varieties containing increased levels antioxidant compounds. In the broad screen for total antioxidant activity, the 47 related, tuber-bearing species showed a wider range of variability than the cultivated varieties and breeding lines. Based on the DPPH assay, antioxidant activity ranged from 103-648 uM trolox equivalents in the cultivated varieties and advanced breeding lines, while that of the wild species was 42-892. HPLC analysis revealed that the phenolic content of the species, and their cultivated counterparts, was primarily composed of caffeic and chlorogenic acids. Other phenolics identified were p-coumaric acid, rutin hydrate, vanillic acid, epicatechin, t-cinnamic acid, gallic acid, and salicylic acid. The highest phenolic content discovered in the accessions was five-fold higher than the highest of the cultivated genotypes. Carotenoid analysis revealed lutein in the accessions, but the yellow-flesh breeding lines were much higher in carotenoids. In addition to the work conducted on antioxidants, an attempt was made to separate intraclonal variants of the potato cultivar Russet Norkotah. Eleven microsatellite primers and 112 AFLP primer combinations failed to produce any reproducible polymorphisms. The inability to detect differences between the clones could be due to the tetraploid nature of the clones or epigenetic differences not detected by the procedures utilized in this study.