Analyzing cranberry bioactive compounds.

There is a growing public interest for the North American cranberry (Vaccinium macrocarpon) as a functional food because of the potential health benefits linked to phytochemical compounds present in the fruit--the anthocyanin pigments, responsible for its brilliant red color, and other secondary plant metabolites (flavonols, flavan-3-ols, proanthocyanidins, and phenolic acid derivatives). Isolation of these phenolic compounds and flavonoids from a sample matrix is a prerequisite to any comprehensive analysis scheme. By far the most widely employed analytical technique for the characterization of these compounds has been high-performance liquid chromatography(HPLC) coupled with ultraviolet-visible(UV/Vis) and mass spectrometer(MS) detection. This review covers the cranberry major bioactive compounds, the extraction and purification methods, and the analytical conditions for HPLC used to characterize them. Extraction, chromatographic separation and detection strategies, analyte determinations, and applications in HPLC are discussed and the information regarding methods of specific cranberry analyte analyses has been summarized in tabular form to provide a means of rapid access to information pertinent to the reader.

Bioactive compounds in cranberries and their biological properties.

Cranberries are healthy fruit that contribute color, flavor, nutritional value, and functionality. They are one of only three fruits native to America. Over the past decade, public interest for the North American cranberry (Vaccinium macrocarpon) has been rising with reports of their potential health benefits linked to the numerous phytochemicals present in the fruit--the anthocyanins, the flavonols, the flavan-3-ols, the proanthocyanidins, and the phenolic acid derivatives. The presence of these phytochemicals appears to be responsible for the cranberry property of preventing many diseases and infections, including cardiovascular diseases, various cancers, and infections involving the urinary tract, dental health, and Helicobacter pylori-induced stomach ulcers and cancers. Recent years have seen important breakthroughs in our understanding of the mechanisms through which these compounds exert their beneficial biological effects, yet these remain to be scientifically substantiated. In this paper these characteristics, as well as the antioxidant, radical scavenging, antibacterial, antimutagen, and anticarcinogen properties of cranberry major bioactive compounds are explained.

Response of onion plants to arbuscular mycorrhizae : 2. Effects of nitrogen fertilization on biomass and bulb firmness.

The effects of N fertilization on growth and root colonization of preinoculated onion (Allium cepa L. cv. Improved Autumn Spice) were studied. Onion transplants, inoculated with either Glomus intraradices, G. versiforme or nothing at sowing, were grown under three levels of N in soils which had either been irradiated, irradiated and amended with nonmycorrhizal microflora, or not irradiated. Interactions between inoculation and soil treatment had a significant effect on dry biomass and final bulb diameter. Control plants cultivated in non-irradiated natural soil grew normally because of the presence of indigenous arbuscular mycorrhizae, but control plants in irradiated soils were stunted. There was no such difference among inoculated plants. In non-irradiated natural soil, bulbs of onions inoculated with G. intraradices or G. versiforme were significantly firmer than bulbs of control plants. Bulb firmness decreased as N fertilization level increased. In non-irradiated natural soil, tissue P concentration of onion plants preinoculated with either fungus was significantly higher than that of control plants. In all soil types, N, P, and Zn concentrations were higher in onion plants colonized by G. versiforme than in those colonized by G. intraradices. The opposite was true of Mn tissue concentration.

Growth of and aflatoxin production by Aspergillus flavus in peanuts stored under modified atmosphere packaging (MAP) conditions.

The combined effects of water activity (aw), storage temperature, headspace oxygen and carbon dioxide concentrations on the growth of, and aflatoxin production by Aspergillus flavus on sterile peanuts were examined using a process optimization technique termed response surface methodology (RSM). Regression analysis of the data indicated that aw, storage temperature and initial headspace oxygen concentration were all significant factors (P < 0.001) affecting the growth of, and aflatoxin production by A. flavus. Extensive growth and aflatoxin production occurred during the first week of storage in most treatment combinations. Maximum growth occurred in peanuts with an aw of 0.97, a storage temperature of 25 degrees C and headspace oxygen of 10% (balance 60:40 carbon dioxide:nitrogen), after 21 days of storage while maximum aflatoxin production occurred at a lower aw of 0.94, after 21 days under similar storage/gaseous conditions. In several treatment combinations, where high levels of aflatoxin (> 20 ng/g) were initially detected, aflatoxin concentration decreased during storage to levels less than the current regulatory limit of 20 ng/g. This study has shown that A. flavus can grow and produce aflatoxin in carbon dioxide enriched atmospheres in the presence of oxygen. It also emphasizes the combined effect of several 'barriers' to inhibit and reduce aflatoxin in MAP products containing various levels of residual oxygen.

Controlled-Atmosphere Storage of Pork Under Carbon Dioxide.

Fresh pork loin slices were packaged under three different anoxic atmospheres (100% N2, 100% CO2 and 50% N2 + 50% CO2) and kept at two storage temperatures (-1°C and 4°C) and two pressures (1.0 and 1.2 atm.) in reusable, gas impermeable metal boxes. A gas headspace to meat weight ratio of >31 per kg was maintained. Carbon dioxide concentrations were unchanged (controlled) during storage. Microbiological, biochemical and physical measurements were made during the 3-week storage period. While atmospheric pressure did not have a significant impact on shelf-life, samples stored at -1°C were satisfactory at 21 days in both CO2 treatments. Samples under N2 did not fare so well, showing higher levels of psychrotrophic bacteria after 18 days at -1°C and 14 days at 4°C. Samples kept in N2 at 4°C were spoiled within 2 weeks. Bacterial growth was slowest under 100% CO2, but samples stored under 50%-50% N2-CO2 at 4°C were also observed to be in good microbiological condition at 21 days of storage. Use of CO2-containing atmospheres provided more than 7 extra days of shelf-life at 4°C over that attainable under 100% N2. Shelf-life at -1°C was improved by 3 to 4 days over that at 4°C. Except for the length of time in storage, treatments had only a minor effect on pH, color, water holding capacity and shear force. These physicochemical characteristics were not factors which limited shelf-life.

Production of Leuconostoc oenos Biomass under pH Control.

Leuconostoc oenos was grown on apple juice-based media. The effect of pH control on metabolism and biomass production was studied. Without pH control, L. oenos acidified the apple juice media to approximately pH 3.6. More than 75% of the malic acid was used under these conditions, but less than half of the carbohydrates was assimilated. Under pH control, biomass yields increased by 60%; most of the malic acid was used, but high levels of unfermented carbohydrates remained. The addition of tomato juice, vitamins, nucleotides, Mn, and malic acid did not permit further increases in the cell counts; however, malic acid did induce further acidification. Growth without pH control favored a more homofermentative metabolism. Biomass production was higher in filter-sterilized apple juice media compared with that in the autoclaved media.

Ionic determinants of spontaneous activity in clusters of cultured cardiac cells from newborn rats.

The spontaneous activity of cell clusters derived from ventricle cells of newborn rats was studied using a recording television microscope. The influence of varying concentrations of sodium, potassium, calcium, tetrodotoxin (TTX), and that of 2 mM MnCl2 was tested. The spontaneous activity of the cell clusters persisted in TTX but it was abolished by Mn. The beating rate increased when [Ca]0 and [Na]0 were changed from 0.3 mM to 3.0 mM and from 30 mM to 75 mM; it decreased with a change of [Na]0 from 75 mM to 142 mM. It is concluded that electrogenesis in their behavior to very young embryonic rat heart cells or cells of the rabbit sinoauricular node.

The effect of bile and of sodium taurocholate on the epithelial cell dynamics of the rat small intestine.

The absence of bile from the intestinal lumen of rats for a period of 48 hr led to: a decreased proliferative cell pool, reduced cell shedding, and a 50% decrease of the labeling index in the ileum. The constant duodenal perfusion of Na taurocholate for periods of 48, 60, 72, and 96 hr in animals with a biliary diversion was associated with: deepening of crypts and decreased crypt/villus ratios as well as with acceleration of the epithelial cell migration rate on the crypt-villus units. The data suggest that bile and bile acids constitute important regulatory factors influencing enterocyte proliferation, migration and loss.