Anthocyanidins, prepared by the acid hydrolysis of black bean and blackberry anthocyanins, were deposited in C18 solid-phase extraction (SPE) cartridges from four different manufacturers. The amount of the black bean anthocyanidins, delphinidin, petunidin, and malvidin (monitored at 520 nm) was unchanged for the first 7 days of storage in SPE cartridges under nitrogen atmosphere at 2 °C. After 45 days of storage the level of delphinidin, petunidin, and malvidin was reduced to 82, 63, and 49% of the original content, respectively. In contrast, the level of delphinidin, petunidin, and malvidin decreased to 17, 10, and 3%, respectively, of the original amount when these anthocyanidins were stored for 3 days in acidic methanol (0.01% HCl) at 2 °C. Similarly, after 46 days of storage in SPE cartridges under nitrogen atmosphere at 2 °C the amount of cyanidin (obtained from evergreen blackberry puree) decreased to 75% of the original content. Cyanidin almost completely disappeared (only 0.2% remained) when it was stored for 4 days in acidic methanol (0.01% HCl) at 2 °C. Anthocyanidin stability was markedly different depending on the brand of the SPE cartridge on which it was stored. Keywords: Solid-phase extraction; anthocyanidin stabilization; delphinidin; petunidin; malvidin; cyanidin
Cereal Chem. 83(2):152-156 Wheat bran was extruded in a twin-screw extruder at five specific mechanical energy (SME) levels (0.120, 0.177, 0.234, 0.291, and 0.358 kWh/kg, dwb) and the cholesterol-lowering effects were compared with those of unprocessed wheat bran when fed to four-week-old male golden Syrian hamsters (n = 10/treatment) for three weeks. Diets contained 10% total dietary fiber, 10.3% fat, 3% nitrogen, and 0.4% cholesterol. Plasma total cholesterol and very-low-density lipoprotein cholesterol were significantly lower with 0.120 kWh/kg extruded wheat bran diet compared with the unextruded wheat bran control. Total triglycerides were significantly lower with 0.120 and 0.177 kWh/kg wheat bran diets compared with those fed 0.291 and 0.358 kWh/kg extruded wheat bran diets. Cholesterol digestibility, total liver cholesterol, and total liver lipids were significantly lower with all the extruded wheat bran diets compared Many popular foods of cereal origin (ready-to-eat cereals, snacks, and pasta) are produced by extrusion processing. The extrudates have physical and chemical characteristics different from those of the original food (Harper 1979; Linko 1981). These differences depend on the extrusion parameters (energy input, residence time, type of extruder used) and the physical and chemical properties (moisture, fat, and fiber content) of the raw material. Extrusion alters the starch, protein, fat, and fiber components of cereals, forming complexes that may affect cholesterol-lowering properties. Extrusion processing could result in fragmentation of proteins, starches, and nonstarch polysacchandes, creating reactive molecules that may form new linkages that could result in enhancing health potential (Camire 1998). Wheat bran in general does not lower cholesterol. In many studies, wheat bran has been used as a control treatment to evaluate cholesterol-lowering effects of other cereals (
Summary:Black bean purée and drum-dried flake microstructures were studied and compared with raw bean by light and scanning electron microscopies. Results illustrate the value of microscopy as a tool for evaluating physical and chemical changes in bean components due to processing. Microscopy was employed to follow the microstructural changes during the processing of black beans by looking at the intermediate product (the purée) and the end product (the flake). The consequences of processing on storage components such as starch, proteins, lipids, and cell walls were elucidated. The bean purée contained starch granules within intact cells and seed coat fragments throughout the product. The drum-dried flakes had a rough exterior, and starch granules were also found within intact cells. Both starch granules and seed coat fragments were found in the drum-dried flake matrices. Protein bodies, occurring in the raw bean, were present (but less obvious than in the raw bean) in both the bean purée and the drumdried flake. Cell contents that no longer occurred in intact cells consisted of fused protein bodies in both products. The seed coat did not change significantly during processing, and pieces of seed coat were easily differentiated throughout the bean purée and the drum-dried flakes. The endosperm, which is closely adherent to the inner portion of the seed coat in the intact bean, was no longer evident in the processed samples, presumably because the endosperm tissue had completely solubilized following the addition of water. Lipids occurred as small droplets and were located throughout both the bean purée and the drum-dried flakes. The bean purée consisted mostly of clumps of intact cotyledon cells with very few broken cells. The cotyledon cells contained intact starch granules with no evidence of starch gelatinization [i.e., the irreversible breakdown of the granule structure (Dengate 1984)]. Free starch granules in the purée, resulting from broken cells, were slightly swollen and had begun to gelatinize. Protein bodies were still evident in the purée, but no longer stained as in the raw, mature bean. The drum-dried flakes contained intact and broken cotyledon cells. Intact cells contained protein bodies that were difficult to detect and appeared to be a rather continuous protein matrix. The cotyledon cells also contained partially gelatinized starch granules that remained mostly distinct but were beginning to fuse. Starch granules interspersed between intact cells were fused and completely gelatinized. The drum-dried flake matrix consisted of a continuous mixture of protein, starch, and cell wall material.
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