Key Aroma Compounds in Oats and Oat Cereals.

Oats possess a unique flavor, comprising grain and nut-like sensory characteristics. The first comprehensive study of oat flavor by Heydanek and McGorrin [ Heydanek , M. G. ; McGorrin , R. J. Gas chromatography-mass spectroscopy investigations on the flavor chemistry of oat groats . J. Agric. Food Chem. 1981 , 29 ( 5 ), 950 - 954 , 10.1021/jf00107a016 ] identified 110 volatile components in oat groats, including C8-C9 unsaturated aldehydes and ketones contributing raw oat grain, hay-feedy, and grassy aromas. A following study on heat-processed oats and cooked oatmeal by Heydanek and McGorrin ( Heydanek , M. G. ; McGorrin , R. J. Oat flavor chemistry: Principles and prospects . In Oats: Chemistry and Technology , 1 st ed.; Webster , F. H. , Ed.; AACC International : St. Paul, MN , 1986 ; pp 335 - 369 ) identified a series of Maillard-derived compounds, including furanones, thiazoles, and 2-methyl-, 2,5-dimethyl-, C3-, and C4-substituted pyrazines. In the subsequent 38 years since these initial research findings, additional identifications of aroma compounds in oat flakes and flours have been reported. This review addresses significant recent developments of the current understanding of oat flavor chemistry and the key aroma compounds that contribute to the unique flavor of oat cereals.

Moisture Adsorption Isotherm and Storability of Hazelnut Inshells and Kernels Produced in Oregon, USA.

Moisture adsorption isotherms and storability of dried hazelnut inshells and kernels produced in Oregon were evaluated and compared among cultivars, including Barcelona, Yamhill, and Jefferson. Experimental moisture adsorption data fitted to Guggenheim-Anderson-de Boer (GAB) model, showing less hygroscopic properties in Yamhill than other cultivars of inshells and kernels due to lower content of carbohydrate and protein, but higher content of fat. The safe levels of moisture content (MC, dry basis) of dried inshells and kernels for reaching kernel water activity (aw ) ≤0.65 were estimated using the GAB model as 11.3% and 5.0% for Barcelona, 9.4% and 4.2% for Yamhill, and 10.7% and 4.9% for Jefferson, respectively. Storage conditions (2 °C at 85% to 95% relative humidity [RH], 10 °C at 65% to 75% RH, and 27 °C at 35% to 45% RH), times (0, 4, 8, or 12 mo), and packaging methods (atmosphere vs. vacuum) affected MC, aw , bioactive compounds, lipid oxidation, and enzyme activity of dried hazelnut inshells or kernels. For inshells packaged at woven polypropylene bag, MC and aw of inshells and kernels (inside shells) increased at 2 and 10 °C, but decreased at 27 °C during storage. For kernels, lipid oxidation and polyphenol oxidase activity also increased with extended storage time (P < 0.05), and MC and aw of vacuum packaged samples were more stable during storage than those atmospherically packaged ones. Principal component analysis showed correlation of kernel qualities with storage condition, time, and packaging method. This study demonstrated that the ideal storage condition or packaging method varied among cultivars due to their different moisture adsorption and physicochemical and enzymatic stability during storage. PRACTICAL APPLICATION: Moisture adsorption isotherm of hazelnut inshells and kernels is useful for predicting the storability of nuts. This study found that water adsorption and storability varied among the different cultivars of nuts, in which Yamhill was less hygroscopic than Barcelona and Jefferson, thus more stable during storage. For ensuring food safety and quality of nuts during storage, each cultivar of kernels should be dried to a certain level of MC. Lipid oxidation and enzyme activity of kernel could be increased with extended storage time. Vacuum packaging was recommended to kernels for reducing moisture adsorption during storage.

One hundred years of progress in food analysis.

Food and agricultural products comprise complex and diverse chemical mixtures that historically have presented challenges for assessing food safety, nutrient content, stability, and sensory qualities. The analysis of food composition has significantly evolved over the past 100 years, progressing from reliance on predominantly "wet chemistry" laboratory methods from the early to mid-20th century to their gradual replacement by modern instrumental techniques. Pioneering developments in pH instruments, spectrophotometry, chromatography/separations, and spectrometry often had immediate applications to food analysis. Continuous improvements in methodology over this period have led to significant enhancements in analytical accuracy, precision, detection limits, and sample throughput, thereby expanding the practical range of food applications. The growth and infrastructure of the modern global food distribution system heavily relies on food analysis-beyond simple characterization-as a tool for new product development, quality control, regulatory enforcement, and problem-solving.

Cellulose-based chromatography for cellooligosaccharide production.

The potential of using cellulose stationary phases for the chromatographic fractionation of cellooligosaccharide preparations has been explored. The impetus for the work is the current interest in using cellooligosaccharides as functional nondigestible oligosaccharides in foods. The conceptual studies illustrate the potential of using ethanol-water mobile phases in conjunction with cellulose stationary phases for cellooligosaccharide fractionation. Cellooligosaccharide solubility in ethanol-water mixtures and their elution order from cellulose-based columns using ethanol-water mobile phases were shown to be in line with their degree of polymerization (DP), with the higher DP cellooligosaccharides being less soluble and having longer retention times. The retention volume for all COS increased with increased temperature. Both microcrystalline and fibrous cellulose preparations were shown to work as chromatographic stationary phases. The application experiments demonstrate the potential of using cellulose stationary phases for the cleanup and fractionation of cellooligosaccharide mixtures generated via acid-catalyzed hydrolysis of cellulose.