The objective of this study was to measure and compare differences in oxidized products of oil extracted from unoxidized and oxidized walnuts using five different extraction methods: (i) mechanical pressing, or solvent extraction with (ii) hexane, (iii) methylene chloride, (iv) chloroform/methanol, or (v) supercritical carbon dioxide (SC-CO 2 ). Of the extraction methods evaluated, only chloroform/methanol and methylene chloride provided reasonable results for all parameters measured (total lipid yield, FA profile, PV, conjugated dienes, FFA content, and volatile content); however, chloroform/methanol extracted significantly greater levels of volatile compounds. The SC-CO 2 extraction with purified gas was simple and accurate for all data except collection of volatile compounds, as these materials are lost during the lipid extraction. Pressing was neither quantitative nor qualitative, and hexane extraction retrieved significantly lower levels of volatiles than the other methods, except for SC-CO 2 .

Texturized soy proteins (TSP) have been produced from hexane-extracted soy flours having a narrow range of characteristics. The objective of this study was to determine the influence of protein dispersibility index (PDI) and residual oil content on extrusion texturization of partially defatted soy flours produced by extruding-expelling (E-E). Ten E-E processed soy flours having residual oil contents and PDI values of 5.5-12.7% and 35.3-69.1%, respectively, were texturized using a twin-screw extruder. Water-holding capacities were greater for TSP prepared from E-E processed soy flours with lower residual oil contents. Bulk densities were significantly lower for TSP prepared from E-E processed soy flours compared with a commercial product made from hexane-extracted soy flour. The texture characteristics of extended ground beef patties containing texturized E-E processed soy flour were similar to that of 19% fat ground beef. Flavor acceptability was directly correlated (R = 0.761) with residual oil content of the E-E processed soy flours. However, lower residual oil and higher PDI flours exhibited better texturization and extrudate qualities.Paper no. J9701 in JAOCS 78, 781-786 (August 2001).

In recent years there has been widespread growth in extruding‐expelling (E‐E) facilities for small‐scale processing of soybeans. To compete in a highly competitive market, these E‐E operations are looking for ways to optimize production of their oil and meal products for values to their customers. The objective of this study was to determine the ranges of residual oil contents and protein dispersibility indices (PDI) possible with E‐E processing of soybeans. We also characterized the partially defatted meal for other factors important in food and feed applications. Residual oil and PDI values ranged from 4.7 to 12.7% and 12.5 to 69.1%, respectively. E‐E conditions significantly influenced residual lipase, lipoxygenase (L1–L3), and trypsin inhibitor activities. Chemical compositions were different for whole, dehulled, and reduced‐moisture soybeans, with dehulled soybeans tending to produce meals having higher residual oil contents at higher PDI values. It was possible to process soybeans with different characteristics (e.g., moisture content, whole, dehulled) to produce meals and flours with wide ranges of properties, providing E‐E operators with opportunities to market value‐added products.

There has been a nationwide growth in small-scale extrusion-expelling (E-E) facilities. In order to compete in a highly competitive market, these E-E operations must look for ways to add value to the resulting products (oil and meal (flour)). One potential use for E-E produced partially defatted soy flour (PDSF) is in the production of texturized soy proteins (TSP). The objectives of this study were to 1) produce and characterize PDSF with a wide range of residual oil (RO) contents and protein dispersability indexes (PDI) using both whole and dehulled soybeans, and 2) determine the influence of RO and PDI on the texturization of PDSF via twin-screw extrusion. RO and PDI ranges in PDSF were 4.73-12.65% and 12.45-69.10, respectively. E-E conditions significantly influenced enzyme (lipase, lipoxygenase (1-3), and trypsin inhibitor) activities, and protein solubility curves of PDSF. For objective 2, ten PDSF were texturized using a Leistritz-18 (Leistritz Corp., Allendale, NJ) twin-screw extruder. Extrusion parameters for texturization were optimized using the median (RO and PDI) PDSF. The influence of RO and PDI on texturization was analyzed using response surface methodology with texture profile analysis (TP A), water holding capacity (WHC) and bulk density (BD) as dependent variables and PDI and RO as independent variables. A TSP-extended ground beef system was evaluated by TP A and a trained sensory panel. In general, lower RO and higher PDI flours exhibited better texturization and extrudate qualities. However, textural, functional and sensory properties of all TSP from E-E produced PDSF were comparable to commercially produced TSP.