INCIDENCE OF AFLATOXIGENIC ISOLATES OF ASPERGILLUS FLAVUS/PARASITICUS OBTAINED FROM GEORGIA CORN PROCESSING PLANTS

Two corn processing facilities within Georgia were evaluated in order to determine the incidence of Aspergillus flavus or A. parasiticus within the plant and in corn harvested and processed in 1984 and 1985. Conidia of A. flavus/parasiticus were found in all corn samples evaluated as well as in settled dust samples taken within these processing facilities. Isolates were obtained by using the differential/selective medium Aspergillus flavus/parasiticus agar. Upon subsequent culture only 55% of the selected isolates were confirmed as belonging to A. flavus/parasiticus group. Some of these isolates were randomly chosen and their ability to produce aflatoxins B₁, B₂, G₁, or G₂ evaluated. Thirty-two percent of the A. flavus/parasiticus isolates cultured for aflatoxin production were found to be aflatoxigenic.     

PATTERN RECOGNITION: PORTABLE COMPUTER PROGRAMS FOR THE FOOD INDUSTRY

Some of the available libraries of pattern recognition programs are tabulated. These include programs ARTHUR (University of Washington), RECOG (Lawrence Livermore Laboratory), and STAG (Fairfield University) the last of which uses both the APL and FORTRAN IV computer languages. The distinction between supervised and unsupervised methods of pattern recognition is presented and the more useful computer algorithms are described. These include programs and literature references for minimal spanning tree, factor analysis, linear dimension reduction, nonlinear dimension reduction, nearest neighbor, and the linear learning machine. The intent is to make the food process industry more aware of the availability of portable computer programs using that branch of artificial intelligence that has come to be termed pattern recognition.     

ELEMENTAL ANALYSIS OF GRASSES AND LEGUMES GROWING ON SOIL COVERING COAL FLY ASH LANDFILL SITES

Forage grasses and legumes growing in the soil covering four coal fly ash landfill sites in Central New York were sampled and analyzed for 20 elements. Selenium, boron and molybdenum were most consistently higher in concentration in these crops than the corresponding control plants sampled from adjacent upwind locations. Legumes absorbed greater amounts of these elements than grasses probably owing to their deep-rooted penetration of the fly ash layer below. Factors affecting the extent of absorption of these elements by the crops and the agricultural significance as related to grazing farm animals are discussed.     

Softening of Canned Apricots: A Chelation Hypothesis

Infiltration of apricot (Prunus armeniaca L.), Patterson cultivar fruits, which are susceptible to rapid softening, with calcium chloride before processing resulted in definite firming of the canned apricots. Non-susceptible fruits treated with citrate buffers (pH 3.7) showed dramatic post-process softening. In individual, untreated, early, green fruit, firmness after processing was directly correlated with the bound calcium:citrate ratio. Based on a chelation hypothesis, it was proposed that softening was accelerated when chelators such as organic acid anions removed structural calcium from the cell wall once cell membranes were lysed by heating.     

Image analysis for grain shape characterization in lamp filaments

Algorithms have been developed for appraising the quality of tungsten lamp filament wire microstructure with respect to its resistance to sag. They allow a numerical determination of grain aspect ratio, grain boundary contour, angle of boundary with wire diameter, and degree of grain boundary surface convolution. These values are combined algebraically to give a grain shape parameter (GSP) which reliably predicts how resistant the filament is to grain boundary sliding. Measurements are made of thermally etched grain boundaries on scanning electron microscopy (SEM) images of the surfaces on coiled filaments. Data are recorded and parameters computed by means of an image analyzer. The technique has been tested on samples made from the same wire modified in process to have varying strain after the last anneal. It has also been tested on samples purchased from various vendors. These applications indicate that the computed GSP is a sensitive predictor of filament creep resistance and reliably reflects variation in wire drawing strain after the last anneal.     

Phytate × Calcium/Zinc Molar Ratios: Are They Predictive of Zinc Bioavailability?

The utility of the phytate/zinc and phytate × calcium/zinc molar ratios for predicting zinc bioavailability from processed soybean foods was investigated. Weight gain and bone zinc accumulation in rats fed various soy protein products were plotted against the calculated molar ratios. The phytate × calcium/zinc ratio was a better predictor of zinc bioavailability in similarly processed products than was the phytate/ zinc ratio. However, in some cases the phytate × calcium/zinc ratio was not effective since some processing procedures apparently altered binding of phytic acid to minerals and other food components.     

Whey Protein Coating Effect on The Oxygen Uptake of Dry Roasted Peanuts

A procedure was developed to coat peanuts with aqueous whey protein isolate (WPI) solutions based on increasing coating-solution viscosity. Oxygen uptake of WPI-coated nuts and uncoated nuts were compared. WPI coatings delayed oxygen uptake of dry roasted peanuts at intermediate (53%) and low (21%) storage relative humidity. They had similar results at 29°C and 37°C. The effects of coating thickness and storage relative humidity indicate that the mechanism of protection of the coatings was through their oxygen barrier properties.     

Emulsifying Properties of Food Proteins: Development of a Standardized Emulsification Method

A recirculating valve-homogenizer was used to compare the emulsifying properties of bovine serum albumin and milk proteins. The energy input per unit volume was directly obtained from the mean maximum valve head pressure per stroke. The mean maximum velocity of the emulsion in the valve head was 83m sec^?1 during a valve opening time of 150 × 10 ^?3 sec reflecting a large velocity gradient per stroke of 4.2 × 10^?6 m³ The method detected changes in the emulsifying activity of proteins resulting from chemical modification, and from process or environmental factors, e.g., ionic strength. The valve-head pressure profile was used to compare the fluidity of the emulsions at different levels of energy input per unit volume (E) and an apparent viscosity index (AVI) has been proposed.