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 lambic's 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.

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.

Reduction in lipid oxidation by incorporation of encapsulated sodium tripolyphosphate in ground turkey.

Ground turkey, with 1% NaCl, was incorporated with no sodium tripolyphosphate (control, nSTP), unencapsulated STP (uSTP; 0.3% or 0.5%), encapsulated STP (eSTP; 0.3% or 0.5% active, phosphate basis), or a blend (0.3% uSTP plus 0.2% eSTP). Encapsulate (hydrogenated vegetable oil) was designed to melt at 74°C. Treatments were stored (4, 24h at 3°C) before being cooked to two different endpoints (EPT; 74, 79°C) followed by post-cooked storage (0, 5, 10days). An improvement of 77% (0.3% eSTP) and 80% (0.5% eSTP) in the reduction of TBARS was found in comparison to corresponding uSTP. The blend produced a 62% improvement compared to uSTP (0.5%) while maintaining cook yield. CIE a* values were highest at both EPT and post-cooked storage times beyond 0 day for eSTP. Meat manufacturing procedures that entail a delayed thermal processing step will benefit by an improvement in lipid oxidation control through the use of encapsulated phosphates.

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.

ORAChromatography and total phenolics content of peanut root extracts.

A large number of compounds have been reported in peanut plants. Many of these compounds are phytoalexins, which are produced by plants experiencing environmental stress and often exhibit antioxidant activity. It is difficult to determine which of the many compounds has the greatest impact on total antioxidant capacity in a mixture. The objectives of this research were to examine the oxygen-radical absorbing capacity (ORAC) value and total phenolic contents of peanut root extracts and peanut root extract fractions collected via HPLC. Peanut roots were extracted from four different cultivars (Brantley, NC-12, Phillips, and Wilson) with 70% aqueous ethanol with ultrasonic assistance. Each cultivar was sampled in duplicate. The extracts were fractionated into 18 3-min fractions by HPLC using a C-18 column. Fractions and crude extracts were freeze dried. ORAC values and total phenolic content were then determined for all fractions and crude extracts. Fractions had a significant effect on the µM TE/mg gallic acid equivalents (GAE). ORAC values ranged from -46.89 µM TE to 185 µM TE in HPLC fractions. ORAChromatography can be used to focus on antioxidants in complex samples.

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 ß-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.

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 University's anaerobic roll-tube procedure and the repair-detection technique for detecting stressed cells. Mara and Oragui's 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.