| 1. |
- Börjesson, Thomas S., et al.
(författare)
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Off-odorous compounds produced by molds on oatmeal agar : Identification and relation to other growth characteristics
- 1993
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Ingår i: Journal of Agricultural and Food Chemistry. - Washington : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 41:11, s. 2104-2111
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Tidskriftsartikel (refereegranskat)abstract
- Ten Penicillium and Aspergillus species, four with a strong musty off-odor and six reference fungi without any characteristic odor, were cultivated on oatmeal agar for 5 days in cultivation vessels provided with an inlet and an outlet for air. Samples of volatile metabolites were collected on a porous polymer adsorbent attached to the outlet from day 2 through day 5 after inoculation. Adsorbed compounds were desorbed thermally and analyzed with GC/MS and a combined GC and sensory analysis, the GC sniff technique. Multivariate analysis of GC/MS and fungal odor data revealed strong associations between 6 of 65 volatile compounds and musty off-odor. The GC sniff technique showed that five of these, dimethyl disulfide, 1-octen-3-ol, 2-methylisoborneol, and two C11H18 compounds, had prominent off-odors. In addition, geosmin, 1-methoxy-3-methylbenzene, and methylphenol were produced in large amounts by some off-odorous fungi and contributed to their unpleasant odor. 3-Methylfuran, 2-methyl-1-propanol, and 3-methyl-1-butanol were much more commonly produced than the off-odorous compounds. Both odorous and other volatile metabolites could be detected after 2 days of fungal growth. The production of odorous metabolites was enhanced at the time of sporulation.
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| 2. |
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| 3. |
- Tovar, Juscelino, et al.
(författare)
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Analytical and Nutritional Implications of Limited Enzymic Availability of Starch in Cooked Red Kidney Beans
- 1990
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 38:2, s. 488-493
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Tidskriftsartikel (refereegranskat)abstract
- Measured with an enzymic method, the starch content of a raw red kidney bean (Phaseolus vulgaris) flour (RBF) was higher than that of a cooked and blended (CBB) and of a cooked, freeze-dried, and milled (CBF) preparation of the seeds. Wet homogenization as well as pepsin pretreatment of CBF increased the starch yield, indicating that starch in the cooked samples is not completely available to enzymic degradation unless cell wall entrapped granules are released by mechanical or enzymatic disruption of the fibrous walls. Solubilization of resistant starch in CBF with 2 N KOH resulted in a further increase in measured starch, which reached the RBF value. Influence of encapsulated and resistant starch fractions on dietary fiber values was also noticed. CBF showed remarkably low values of in vitro amylolysis rate and starch digestibility index in a digestion/dialysis system, features that seemed to depend also on the integrity of cell walls.
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| 4. |
- Tovar, Juscelino, et al.
(författare)
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Effect of Processing on Blood Glucose and Insulin Responses to Starch in Legumes
- 1992
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 40:10, s. 1846-1851
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Tidskriftsartikel (refereegranskat)abstract
- Postprandial glycemic and insulinemic responses to variously processed red kidney beans were evaluated in normal subjects. The dried seeds were (a) boiled; (b) autoclaved; (c) boiled, freeze-dried, and milled to obtain a precooked flour (PCF) rich in cell-enclosed starch; or (d) milled, steam-cooked, and freezedried to yield a flour containing free starch (FSF). All bean products elicited lower metabolic responses than white wheat bread, used as a reference. Judged from the glycemic and insulinemic indices and the postprandial peak concentrations, autoclaved beans, PCF, and FSF had a more “rapid” behavior than the boiled seeds. Responses to autoclaved beans and PCF were intermediate between boiled beans and the FSF. The insulinemic indices of a lentil PCF and white bread were similar, indicating that different legumes may have different susceptibilities to processing. It is concluded that both the cellular and the cotyledon tissue structures are important determinants of the metabolic responses to legumes.
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| 5. |
- Tovar, Juscelino, et al.
(författare)
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Starch Content and α-Amylolysis Rate in Precooked Legume Flours
- 1990
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 38:9, s. 1818-1823
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Tidskriftsartikel (refereegranskat)abstract
- Dried lentils (Lens culinaris) and beans (Phaseolus vulgaris, black, brown, white, and red) were boiled until soft, freeze-dried, and milled. This procedure yielded precooked flours (PCF), rich in intact cells filled with starch granules. Starch content in the various bean PCFs was underestimated by enzymic assays. Potentially available starch in PCFs was evaluated after complete release of starch by mechanical disruption of cell wall structures. Total starch content, measured after solubilization in 2 N KOH, was higher than the potentially available starch, indicating that all PCFs contained important quantities of resistant starch, i.e., retrograded amylose (3–9%, dwb). Limited enzymic availability of starch in PCFs was also demonstrated by their low -amylolysis rate. Pepsin preincubation and additional heat treatment increased the rate and extent of in vitro enzymic hydrolysis. Considerable differences in susceptibility to a-amylase attack were observed between the various legume flours.
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