Carolyn J. Oles

Precipitation of inulins and oligoglucoses by ethanol and other solvents

Abstract We investigated the ethanol precipitation step of the gravimetric method of dietary fiber analysis (AOAC Official Method 985.29). Four different solvents: ethanol, propanol, acetone and acetonitrile at four ratios: 1:1, 2:1, 3:1 and 4:1 (solvent : supernatant, v/v) were studied. Using inulins that contain components with a full range of degree of polymerization values (DP), we found that the percents of precipitation by these solvents were proportional to the average DP of the products. Use of ethanol and propanol produced similar results. In general, acetonitrile and acetone precipitated more of the inulins than did ethanol. Supernatant solutions were analyzed by high performance anion exchange chromatography in order to determine the size of the components that were precipitated. Our data showed that components of inulin with DP 1–10 remain in solution after the addition of ethanol at a ratio of 4:1. However, significant amounts of molecules of DP 11 and 12 and smaller amounts of molecules of DP 14–18 also remain in solution. The precipitation patterns of oligoglucoses with DP 1–DP 7 were also investigated. Our data suggest that the precipitation behavior of oligoglucoses follows a pattern similar to that of inulins.

Mycotoxins in infant/toddler foods and breakfast cereals in the US retail market

ABSTRACT The objective of this study was to conduct a mycotoxin survey of commercial infant/toddler foods (cereals and teething biscuits) and breakfast cereals in the United States. A total of 215 retail samples were collected from three geographical locations and analysed for aflatoxins, fumonisins, deoxynivalenol, HT-2 toxin, ochratoxin A, T-2 toxin, and zearalenone using a stable isotope dilution liquid-chromatography tandem mass spectrometry (LC-MS/MS) method. One or more mycotoxins were found in 69% (101/147) of the infant/toddler foods and 50% (34/68) of breakfast cereals. Mycotoxin co-occurrence was observed in 12% of infant/toddler foods and 32% of breakfast cereals. However, the concentrations of detected mycotoxins were lower than the current FDA action and guidance levels. Aflatoxins and HT-2 toxin were not detected in any of the samples, while deoxynivalenol was the most frequently detected mycotoxin. Rice-based cereals appeared to be less susceptible to mycotoxin contamination than other cereal types.