William N. Eigel

Antioxidant activities of Vine Tea (Ampelopsis grossedentata) extract and its major component dihydromyricetin in soybean oil and cooked ground beef.

Antioxidant activities of Ampelopsis grossedentata extract (EXT) and its major component dihydromyricetin (DHM) were analysed and compared with BHA in two model systems, soybean oil and cooked ground beef. Oxidation of soybean oil samples was measured using peroxide value, anisidine value, headspace volatiles and headspace oxygen content. TBARS (thiobarbituric acid reactive substances) test was used to measure the oxidation of cooked beef. DHM was more potent than BHA in preventing soybean oil oxidation. EXT was not as effective as BHA or DHM in soybean oil. In cooked beef, all three antioxidants significantly lowered oxidation compared to control, but there were no differences between the three. Mechanisms and potentials of EXT and DHM as natural food antioxidants need to be studied on a case-by-case basis.

Enhancement of Plant Essential Oils' Aqueous Solubility and Stability Using Alpha and Beta Cyclodextrin

Sodium benzoate has been shown to produce benzene in combination with ascorbic acid. This has led to research for safe alternatives from plant essential oils and parabens that have shown some antimicrobial activity, but many of these compounds exhibit poor solubility in aqueous solutions. Cyclodextrins can increase the solubility of many compounds. This work aimed to investigate the solubility of 23 plant essential oils and 4 parabens in water and an apple juice medium. Four of these compounds were chosen for their low aqueous solubility to determine if complexing the compound with α- and β-cyclodextrin would increase solubility. Three of the complexes were dissolved in an acidified aqueous solution and then studied in glass and polyethylene terephthalate (PET) to determine if storage material would affect the stability. Solubility of the 27 compounds in distilled water ranged from 1.6 mg/L to 2460.6 mg/L and the solubility of 18 of the compounds decreased from 2.5 to 84.7% in apple juice medium (pH = 3.4, 12-13 °Brix). Complexation with cyclodextrin dramatically increased the solubility of the compounds, up to 10-fold. Packaging material had no effect on concentration of compounds present over 7 days. Cyclodextrins were able to increase solubility of these compounds to more suitable concentrations, and may lead to viable natural alternatives to sodium benzoate.

Packaging modifications for protecting flavor of extended-shelf-life milk from light

The effectiveness of titanium dioxide (TiO2)-loaded high-density polyethylene (HDPE) to reduce light-induced oxidation of extended-shelf-life milk (2% total fat) was studied. The objective was to determine differences over time in sensory quality, vitamin retention, and oxidative chemistry as a function of packaging and retail light exposure duration. Effectiveness of packaging for protecting milk quality was assessed by sensory evaluation (triangle tests, untrained panel), changes in volatile compounds, thiobarbituric reactive substances (TBARS), and riboflavin concentration. Milk (2%) was stored in HDPE packages consisting of TiO2 at 3 levels (low: 0.6%; medium: 1.3%; high: 4.3%) at 3 °C for up to 43 d. Light-protected (translucent, foil-wrapped) and light-exposed (translucent) HDPE packages served as controls. The high TiO2-HDPE package provided protection similar to light-protected control package through d 22 of light exposure, with less consistent performance by the medium TiO2 package. The TBARS increased in all treatments during storage. Under the experimental conditions used, a TBARS value of 1.3mg/L could be considered the limiting sensory threshold for differentiating oxidized milk from light-protected milk. Riboflavin concentration decreased 10.5% in the light-protected control and 28.5% in the high TiO2 packaged milk past 29 d of light exposure, but losses were greater than 40% for all other packages. The high TiO2 package protected riboflavin concentration from degradation and controlled aldehyde concentration throughout the test period.

Oxidative stability of an extended shelf-life dairy-based beverage system designed to contribute to heart health.

Skim milk, butter-derived aqueous phase, butter oil, and fish oil (3 levels) were used to produce UHT pasteurized n-3 fatty acid-fortified beverages (3.1% fat, 3.9% protein, and 11.5% total solids) with targeted deliveries of 200, 500, and 800 mg of eicosapentaenoic acid and docosahexaenoic acid (combined total) per 250 mL (8 fl oz) serving. Microbial quality, emulsion stability, and oxidation of lipids over 35 d of storage at 4 °C were evaluated. Conjugated diene hydroperoxides were below 1% throughout storage and were found at highest concentrations around d 21 of storage for all formulations. Volatile analysis indicated an increase in 1-penten-3-ol in the n-3 fortified dairy-based beverage systems during storage. Triangle tests were conducted to determine if consumers could detect a difference in aroma, compared with commercially processed aseptically packaged milk. The beverage system with targeted delivery of 500 mg of eicosapentaenoic acid + docosahexaenoic acid per 250-mL serving was not different in aroma compared with commercially available UHT processed milk. This formulation delivered 432 mg of heart-healthy n-3 fatty acids per 250-mL serving on d 35 and was microbiologically and physically stable throughout the 35-d refrigerated storage period.

Light Wavelength Effects on a Lutein-Fortified Model Colloidal Beverage

The effect of light on a model colloidal beverage system containing whey protein, lutein, and limonene was investigated. Changes in volatile chemistry were evaluated under accelerated conditions (12 h, 25 °C) at selected wavelengths regions (395, 463, 516, 567, and 610 nm absorbance maxima) using a photochemical reactor. The most damaging wavelengths to lutein stability were UV (200-400 nm) and 463 nm wavelengths. Hexanal formation was highest in the control beverage when exposed to full spectrum light and UV (200-400 nm) wavelengths. Hexanal also was formed in the lutein-fortified beverage under full spectrum light and UV (200-400 nm) wavelengths but to a significantly lesser degree. Limonene degraded significantly under all treatment conditions, with most degradation occurring during full spectrum light exposure. Lutein fortification did not completely protect limonene from degradation.

Interaction of copper and human salivary proteins.

Interaction of taste molecules with saliva is the first step in the flavor perception process. Saliva is assumed to influence copper-induced sensation by controlling the copper solubility or causing astringency via binding of proteins with copper. This study was performed to identify the nature of copper-protein interactions in relation to the sensory perception of copper. Saliva was treated with CuSO4 x 5H2O at levels of 0, 2.5, 5, 10, 20, or 40 mg/L, and changes in salivary proteins were analyzed using high performance liquid chromatography (HPLC) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Protein peaks that showed changes in HPLC were characterized with SDS-PAGE. HPLC analysis revealed that copper treatment up to 40 mg/L decreased several proteins, including the dominant peak, by 70%. This peak was composed of alpha-amylase, a secretory component, and basic proline-rich proteins. SDS-PAGE results showed that salivary proteins of molecular weight 29 kDa and 33 kDa precipitated when copper was added at concentrations > or =10 mg/L. This study provides biochemical information for understanding perception mechanisms of copper sensation.

Improved recovery of stressed Bifidobacterium from water and frozen yogurt

A roll-tube repair-detection procedure was developed to enumerate injured and noninjured cells of Bifidobacterium species from water and food samples. This procedure combined the Virginia Polytechnic Institute and State Universitys anaerobic roll-tube procedure and the repair-detection technique for detecting stressed cells. Mara and Oraguis human bifid sorbitol agar medium was modified for use in the roll-tube procedure by replacing the indicator bromocresol purple with phenyl red (0.027 g/l), adding 0.0006 g of methylene blue per 1, increasing the agar content to 25 g/l and adjusting the pH of the medium to 7.1 ± 0.1. The repair-detection roll-tube technique was shown to recover Bifidobacterium cells significantly (P < 0.01) better than pour plates, using the same medium incubated in anaerobe jars, even when a repair-detection system was used. Most repair in the roll tubes occurred in the first hour. B. adolescentis had a poor survival rate after 96 hours in water. Glucose was substituted for sorbitol in the medium used for enumeration of B. longum added to frozen yogurt, because this organism cannot utilize sorbitol. This medium, when used as part of a repair detection system, significantly (P < 0.01) recovered more cells than anaerobic pour plate techniques and was able to separate Bifidobacterium species and Lactobacillus acidophilus by colony morphology. Bifidobacterium cells were 1mm or larger, round and yellow, while the L. acidophilus colonies were so small (< 1/4 mm) their detection and enumeration was difficult.

Comparison of Two Extraction Techniques, Solid-Phase Microextraction Versus Continuous Liquid–Liquid Extraction/Solvent-Assisted Flavor Evaporation, for the Analysis of Flavor Compounds in Gueuze Lambic Beer

Lambic is a beer style that undergoes spontaneous fermentation and is traditionally produced in the Payottenland region of Belgium, a valley on the Senne River west of Brussels. This region appears to have the perfect combination of airborne microorganisms required for lambics spontaneous fermentation. Gueuze lambic is a substyle of lambic that is made by mixing young (approximately 1 year) and old (approximately 2 to 3 years) lambics with subsequent bottle conditioning. We compared 2 extraction techniques, solid-phase microextraction (SPME) and continuous liquid-liquid extraction/solvent-assisted flavor evaporation (CCLE/SAFE), for the isolation of volatile compounds in commercially produced gueuze lambic beer. Fifty-four volatile compounds were identified and could be divided into acids (14), alcohols (12), aldehydes (3), esters (20), phenols (3), and miscellaneous (2). SPME extracted a total of 40 volatile compounds, whereas CLLE/SAFE extracted 36 volatile compounds. CLLE/SAFE extracted a greater number of acids than SPME, whereas SPME was able to isolate a greater number of esters. Neither extraction technique proved to be clearly superior and both extraction methods can be utilized for the isolation of volatile compounds found in gueuze lambic beer.

Impact of Dietary Acculturation on the Food Habits, Weight, Blood Pressure, and Fasting Blood Glucose Levels of International College Students

Abstract Objective: This study was conducted to determine the impact of dietary acculturation on the health status of newly arrived international students at Virginia Tech in Fall 2010. Participants: Thirty-five international students, 18–36 years of age, completed the study. Methods: Data were collected at 3 different time periods (V1, V2, and V3) approximately 6 weeks apart. A food frequency– and dietary pattern–related questionnaire was administered and numerically coded responses were analyzed. Twenty-four-hour dietary recall data were also collected at V1, V2, and V3. Body weight, fasting blood glucose level, and blood pressure of study participants were also determined at each time period. Results: Total sample population (TSP) had a significant increase in mean weight of 2.79 lb from visit 1 (V1) to visit 3 (V3) (p = .0082). Ten participants gained an average of 9.0 lb (participants who gained weight; n = 10). There was also an increase in the frequency of consumption of high-calorie American food items from V1 to V3. However, there were no significant changes in mean systolic blood pressure and mean fasting blood glucose was significantly lower at V3 than at V1. Conclusions: There was a gradual shift in the dietary patterns of international students towards the American diet. Dietary acculturation led to weight gain among some of the students, which may potentially have a negative impact on their health status if continued for longer time periods.

Antioxidative effects of encapsulated sodium tripolyphosphate and encapsulated sodium acid pyrophosphate in ground beef patties cooked immediately after antioxidant incorporation and stored

Ground beef with 1% NaCl was incorporated with 0.5% unencapsulated sodium tripolyphosphate (uSTP), 0.5% encapsulated sodium tripolyphosphate (eSTP), 0.5% unencapsulated sodium acid pyrophosphate (uSAPP), or 0.5% encapsulated sodium acid pyrophosphate (eSAPP) prior to being cooked and stored (0 or 6 d, 3 °C). The pH was higher (P<0.05) for sodium tripolyphosphate samples (6 d: uSTP 5.98; eSTP 5.89) and lower (P<0.05) for sodium acid pyrophosphate (6 d: uSAPP 5.31, eSAPP 5.33) samples than control sample (6 d, 5.50). Overall, samples with uSTP had the least cooking loss and lowest TBARS values. TBARS (mg/kg) for the phosphate treatments were lower (P<0.05; ave. 1.78, 0 d; 3.49, 6 d) than for the control samples (3.07, 0 d; 22.85, 6 d). Therefore, phosphate incorporation into ground beef prior to cooking aids in the reduction of oxidation in the cooked, stored product, although a longer period of time before thermal processing may be necessary for the encapsulated phosphate to have significant benefits.