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1.
Juxing Chen Karen Wedekind Jeffery Escobar Mercedes Vazquez-Añón 《Journal of the American Oil Chemists' Society》2020,97(10):1151-1163
Trypsin inhibitor (TI) and urease activity (UA) are the most relevant quality aspects of soybean meal (SBM) for monogastric animals. This study’s objective was to determine the levels of TI and UA in SBM collected from feed mills in different countries, whether TI and UA are correlated since they are both heat-labile, and impact of TI on pig ileal amino acid digestibility. TI was 1.20–8.37 mg g−1 with 36.4% samples <3 mg g−1, UA was 0–0.311 ΔpH unit with 64.2% samples <0.05 ΔpH unit in 847 solvent-extracted SBM samples. TI and UA results varied by countries and world areas. By country, mean TI was highest in Germany and lowest in Philippines, mean UA was highest in India and lowest in Philippines. By world areas, mean TI was highest in Latin America and lowest in North America, UA was highest in Asia and lowest in Latin America. TI and UA results vary in different soybean products, TI ranked as raw soybeans > expeller SBM > full-fat-extruded (FFE) SBM ≥ heat-inactivated full-fat (HIFF) SBM > solvent-extracted SBM; UA ranked as raw soybeans > HIFF SBM > FFE SBM ≥ solvent-extracted SBM ≥ expeller SBM. TI was not correlated with UA in 847 solvent-extracted SBM, suggesting that UA may not be used as a surrogate indicator for TI. A diet contained 38% SBM with 8.78 mg g−1 TI significantly reduced apparent ileal digestibility of amino acids and crude protein by 13.3–26.0% and 23.3% points, respectively, in cannulated pigs compared to SBM with 2.51 mg g−1 TI. 相似文献
2.
Keshun Liu 《Journal of the American Oil Chemists' Society》2021,98(4):355-373
For expressing trypsin inhibitor activity (TIA), trypsin units inhibited (TUI), trypsin inhibited, and trypsin inhibitors have been used. Although the last two units are preferred, their calculations in current practices require refinement. With the proposed AOCS method Ba 12a-2020, four experiments were conducted, using four trypsin preparations having specific activity of 11,625, 12,602, 13,728, and 14,926 Nα-benzoyl-L-arginine ethyl ester (BAEE) units/mg protein, respectively. Experiment 1 determined the relationship between absorbance at 410 nm (A410) and trypsin concentration. Experiment 2 involved assaying raw and heated soybeans, expressing TIA as TUI/mg sample and μg trypsin inhibited/mg sample, and determining conversion factors between the two units. Experiment 3 resembled Experiment 2 except for using purified soybean Kunitz inhibitor (KTI) and Bowman-Birk inhibitor (BBI). Conversion factors determined correlated highly with trypsin-specific activity (R2 = 0.9789). After standardizing against a reference trypsin having 15,000 BAEE units/mg protein, a standardized conversion factor of 0.03 A410 (1.5 TUI) = 1 μg trypsin inhibited was determined. It remained consistent regardless of trypsin specific activity, with or without inhibitors, and type of inhibitor samples. By using purified inhibitors (Experiment 3), conversion values between TUI and μg trypsin inhibitor and between μg trypsin inhibited and μg trypsin inhibitor could also be calculated, enabling expression of TIA in amounts of pure KTI, BBI or their equivalents. Furthermore, when the AOCS method was modified with half substrate concentration, half trypsin concentration or half both (Experiment 4), TIA values in TUI could change with modifications but values in mg trypsin inhibited (standardized) or trypsin inhibitor remained consistent. 相似文献
3.
Keshun Liu 《Journal of the American Oil Chemists' Society》2021,98(12):1115-1129
For measuring trypsin inhibitor activity (TIA), there are two major official methods: American Oil Chemists Society (AOCS) method Ba 12a-2020 and International Organization for Standardization (ISO) 14902:2001. The former was recently approved. The two methods differ in sample preparation, extraction, colorimetric assay systems and TIA calculations. In this study, the two methods were symmetrically compared using three unique sets of samples: assorted protein products of soybeans, pulses, and grains; soybeans boiled for varied durations; and soy white flakes toasted for varied durations. For given samples, significant differences existed in TIA measured by the two methods, resulting from effects related to the assay systems and TIA calculations, not from the difference in sample preparation and extraction. When the same trypsin was used, TIA (in mg trypsin inhibited/g sample) measured by the two methods were highly correlated (r = 0.9973, n = 27), giving an equation of y = 0.5464x − 0.4887, where y represents ISO values and x for AOCS values. The line connecting ratios of ISO/AOCS in TIA and AOCS values remained relatively flat around 0.53 but started to curve down when TIA approached the lowest. Furthermore, for the same samples, TIA values measured by the ISO method decreased with increasing specific activity of trypsin used, while AOCS values remained consistent, leading to decreasing ratios of ISO/AOCS. Therefore, accurate and direct comparison of the two methods was impossible. It could not be resolved by simply changing ISO method's calculations as hypothesized earlier. Regardless, for most samples, ISO values were roughly about 55% of AOCS values. 相似文献
4.
Jianhua Huang Zhengmei Zhao Linya Shao Chang Chang Xuemei Sun Xiaosan Wang Qingzhe Jin Xingguo Wang 《Journal of the American Oil Chemists' Society》2021,98(7):747-756
The objective of this study was to improve the content of docosahexaenoic acid (DHA) and obtain the blended oils used for different cooking methods (steaming, boiling, and stir-frying) by blending 0%–15% DHA algal oil into soybean oil. It was shown that the addition of DHA algal oil increased saturated fatty acid (SFA) (1.57%) but decreased monounsaturated fatty acid (MUFA) (0.76%) and polyunsaturated fatty acid (PUFA) (0.68%). Various cooking methods significantly changed the fatty acid (FA) compositions. Steaming is a more effective way to prevent DHA loss and the production of trans-fatty acid than boiling and stir-frying. Besides, a positive result from free fatty acid (FFA) and peroxide value also demonstrated that steaming was a better way to protect oils. Overall, the soybean oil blended with 3% DHA algal oil with better oxidative stability and could be recommended for daily application by steaming. 相似文献
5.
L. B. Carew Jr. F. W. Hill M. C. Nesheim 《Journal of the American Oil Chemists' Society》1961,38(5):249-253
Experiments were conducted to evaluate heated unextracted soybean fractions as sources of soybean oil and protein for the
growing chick. Heated dehulled unextracted soybean flakes produced growth rate and feed efficiency equal to that obtained
with the combination of soybean oil meal and degummed soybean oil while heated ground unextracted soybeans were less satisfactory
in this respect. The poorer results obtained with ground unextracted soybeans were shown to be related to a poorer absorbability
of the oil in them. Flaking the soybeans markedly improved the absorbability of the oil by the chick, probably by causing
a greater disruption of cellular structure than was obtained by the grinding of the soybeans. The metabolizable energy of
ground unextracted soybeans was substantially less than that of unextracted soybean flakes. Most of the differences in metabolizable
energy were accounted for by differences in absorbability of the oil.
Soybean hulls at a level equivalent to that contained in soybeans were found to have no effect on growth rate and only a slight
effect on feed efficiency. Autoclaving soybean oil did not lower its value for the chick. The relationship between the poorer
growth obtained with ground unextracted soybeans and the low absorbability of the oil in them was discussed.
To obtain maximum efficiency in the use of unextracted soybean products in chick rations, some such means as flaking must
first be employed to increase the availability of the oil. 相似文献
6.
Muhammad Kaleem Yves Farizon Francis Enjalbert Annabelle Troegeler‐Meynadier 《European Journal of Lipid Science and Technology》2013,115(2):161-169
Heating oilseeds has been shown to improve the milk fatty acid profile when given to dairy cows, compared to raw oilseeds. However, results from published studies are conflicting. The conditions of heating and storage of the oilseeds could be responsible for these differences, probably partly through their effects on lipid oxidation, the products of which could act on ruminal biohydrogenation (BH). Thus, 15 different treatments were applied to ground soybeans: three levels of heating (no heating, 30 min at 110 or 150°C) × 5 ambient storage durations (0, 1, 2, 4, or 6 months). Soybeans were incubated in vitro with ruminal fluid for 6 h. Triacylglycerol (TAG) polymers, hydroperoxides and hydroxyacids (HOA), aldehydes, and fatty acids were assayed in soybeans and ruminal culture. No TAG polymer was detected in any treatment. Soybeans stored for a long time had a high content of HOA, whereas those heated at 150°C, whatever the storage duration, had high aldehyde contents. The percentage disappearance of cis‐9,cis‐12 18:2 and cis‐9,cis‐12,cis‐15 18:3 in incubates decreased significantly in cultures with heated soybeans, especially at 150°C, suggesting that this partial protection of polyunsaturated fatty acids (PUFA) from BH was at least in part linked to the aldehyde content of the heated soybeans. Practical applications: Oilseeds given to ruminants are often heated, and heat treatment is known to generate oxidation products. Knowing what oxidation products influence ruminal biohydrogenation of unsaturated fatty acids could result in technological processes allowing a better transfer of unsaturated fatty acids from oilseeds to ruminant products. 相似文献
7.
Color reversion in soybean oil can be prevented by reducting the enzyme activity of soybeans before cracking and flaking.
Soybean oil extracted from steamed, intact soybeans (18% moisture) had lower Rm (max. red) values in RBD oil, higher amounts
of γ-tocopherol, plus its isomers, in both crude and RBD oil, and also higher amounts of hydratable phosphatides in crude
oil than those in the oils from the same beans without steam treatment. For soybean pretreatments, a toasting process is less
effective than the steaming process for the inhibition of color reversion of soybean oil. To prevent the occurrence of color
reversion in RBD soybean oil, the amount of γ-tocopherol and γ-TED (5-[tocopheryloxy]-γ-tocopherol) should be above 550 ppm
in crude oil. 相似文献
8.
K. Warner T. L. Mounts W. F. Kwolek 《Journal of the American Oil Chemists' Society》1985,62(10):1483-1486
Room odor characteristics produced by heated soybean oil (SBO) and soybean oils hydrogenated with copper (CuHSBO) and nickel
(NiHSBO) catalysts were evaluated by a trained panel. Oils were intermittently heated to 190 C for total heating periods of
5, 15 and 30 hr. Oil additives investigated included methyl silicone (MS), tertiary butylhydroquinone (TBHQ) and a polymeric
antioxidant in various combinations with citric acid (CA). In room odor tests directly comparing SBO, CuHSBO and NiHSBO, panelists
rated the hydrogenated oils as having significantly less odor intensity than the SBO. The combination of CA+MS had the greatest
effect in lowering odor intensity of the heated oils, followed by the mixture of CA+MS+TBHQ. The low odor intensity of the
MS-treated oils remained fairly constant throughout the tests, while the higher intensity associated with all the other additive-treated
oils decreased with increasing heating times, possibly as the result of formation of more volatile decomposition products
in the initial heating stages. Methyl silicone had the strongest effect of any additive in decreasing objectionable room odors
in the oils. Partially hydrogenated SBO treated with up to 5 ppm of MS produced cooking oils with low room odor intensity
and low color development during prolonged heating. 相似文献
9.
Fritsch C. W. Egberg D. C. Magnuson J. S. 《Journal of the American Oil Chemists' Society》1979,56(8):746-750
A soybean oil, a hydrogenated vegetable frying shortening and an animal-vegetable shortening were heated at 190 C for 8 hours
each day for 4 days with and without the frying of potatoes. Samples were taken periodically and analyzed for various changes
normally used to measure frying oil deterioration. The changes in the dielectric constant were determined with a patented
instrument called the Food Oil Sensor. This instrument is standardized with 3. sample of the fresh oil, and it then measures
the change in the electric capacitance of the heated oil samples. The dielectric constant of all three shortenings increased
linearly with heating time. The greatest change occurred in the soybean oil sample and the smallest change in the hydrogenated
vegetable shortening. For each shortening the increase was somewhat greater during frying than during heating without frying.
Statistically significant correlations were obtained between instrument readings and increase in the total polar materials,
the color, the peroxide values, the diene content, and the free fatty acids and the decrease in the iodine values. 相似文献
10.
Rapeseed, soybean, and sunflower oil were heated for 15 min in a 5-mm oil layer in a pan at 180°C. The fatty acid composition
was almost unaffected by heating, while the polymer content rose slightly and the tocopherol content decreased, except in
soybean oil. The absorption of oils before and after heating was investigated in lymph-cannulated rats. Oils were administered
as emulsions through a gastrostomy tube and lymph was collected during the next 24 h. The highest accumulated lymphatic transport
of total fatty acids was observed after administration of rapeseed oil, and the lowest after heated sunflower oil. The accumulated
transport was similar for all unheated oils. The transport of fatty acids was significantly lower in rats receiving heated
oil compared to those receiving the corresponding unheated oil. Small increases in polymers may have contributed to the decreased
lymphatic transport of oil following heating, although this probably does not fully explain the effect. The absorption of
sunflower oil was more affected by heating than the absorption of soybean or rapeseed oil. Furthermore, the largest decrease
in total activity of tocopherols following heating was observed in sunflower oil. Overall, these results demonstrate that
the absorption of vegetable oils is affected by moderate heating. 相似文献
11.
A. I. Nelson W. B. Wijeratne S. W. Yeh T. M. Wei L. S. Wei 《Journal of the American Oil Chemists' Society》1987,64(9):1341-1347
A new concept is described for mechanical extraction of oil from soybeans, using dry extrusion as a pretreatment. It was found
that coarsely ground whole soybeans at 10 to 14% moisture could be extrusion cooked so that the extrudate emerges from the
die in a semi-fluid state. The dwell time within the extruder was less than 30 seconds, and the temperature was raised to
about 135 C. The semi-fluid extrudate was immediately pressed in a continuous screw press to obtain high quality oil and press
cake. Extrusion prior to expelling greatly increased the throughput of the expeller over the rated capacity. An oil recovery
of 70% was obtained in single pass expelling using pilot model expellers. Higher recovery rates can be expected with commercial
scale expellers. The high temperature-short time extrusion cooking process eliminates the prolonged heating and holding of
raw material in conventional expelling. Under the experimental conditions, press cake with 50% protein, 6% residual oil and
90% inactivation of trypsin inhibitors was obtained. The low fat cake was easily ground in a hammer mill without the usual
problems associated with milling of whole beans. The expelled oil was remarkably stable with an AOM stability of 15 hr, which
is comparable to refined deodorized oil according to NSPA specifications. The new procedure offers potential for producing
natural soybean oil and food grade low fat soy flour by a relatively low cost operation. It may be adopted as an improvement
to existing conventional expelling operations in less developed countries or as a commercial or on-farm operation for producing
value added products from soybeans within the U.S. 相似文献
12.
The state of soybeans prior to extraction affected the tocopherol content of crude soybean oils. Soybean flakes with a thickness
of 0.16–0.33 mm had higher extracted oil yield but a slightly lower tocopherol content of the oils than did cracked beans
and thicker bean flakes. Highmoisture content and long storage of soybeans resulted in lower tocopherol content in the crude
oils, with moisture content being more important than storage time at decreasing the tocopherol content of oils. Soybean oil
from stored beans with 15±1% moisture content led to a more significant decrease in the tocopherol content than did oil from
stored beans with low (12%) or high (18%) moisture contents. Soybean flakes contaminated with oxidized oil had a significant
effect on the decrease of the tocopherol content in crude oils. The high amount of phospholipids in crude soybean oil might
result in a smaller decrease in the tocopherol content of oil during heating. 相似文献
13.
This paper reports the state of the art of the microwave super‐heated boiling phenomenon. When a liquid is heated by microwaves, the temperature increases rapidly to reach a steady temperature while refluxing. It happens that this steady state temperature can be up to 40 K higher than the boiling point of the liquid. With the same reactor, overheating is not observed under conventional heating. The bulk temperature of a microwaved solvent under boiling depends on many factors: physical properties of the solvent, reactor geometry, mass flow, heat flow, and electric field distribution. The influence of these factors is studied and discussed. The kinetics of homogeneous organic reactions shows an extension of Arrhenius behaviour into the super‐heated temperature region. Reaction rate enhancement of order 10–100 can thus be achieved, which is normally only possible under pressure. Finally, we present a model predicting reaction kinetics and yields under classical and microwave heating, based on predicted temperature profiles in agreement with experimental data. 相似文献
14.
RAMON L. SAGER HENRI TAWIL D. P. H. HASSELMAN 《Journal of the American Ceramic Society》1984,67(10):651-653
A model study was conducted of the thermal fatigue and single-cycle thermal shock resistance of indented soda-lime-glass rods heated over durations sufficiently short that thermal equilibrium was not reached prior to quenching into a water bath. The experimental results indicate that for short heating periods thermal fatigue life at fixed ΔT and the critical quenching temperature difference (Δ7c ) for a single-cycle quench significantly exceed the corresponding values obtained for specimens heated for sufficiently long periods that conditions of final thermal equilibrium were obtained prior to quenching. The implications of these results for single-cycle and multicycle thermal shock testing are discussed. 相似文献
15.
目前对螺旋管在其管外表面均匀受热,管内两相流动换热的研究已十分丰富;但是在其管外表面非均匀受热条件下,管内两相流动沸腾换热特性的研究鲜有报道。为了解决螺旋管在实际运用中遇到的非均匀受热问题、得到其换热特性,本文采用了实验的方法研究了卧式螺旋管周向非均匀受热条件下管内流动沸腾换热特性。其中实验工况范围为系统压力P=0.7~1.0MPa,质量流速G=181~364kg/(m2·s),质量干度χ=0.07~0.69。实验考察了螺旋管管外壁在两种非均匀受热条件下管内的两相流动沸腾换热系数与热流密度、质量流速、质量干度的关系,并与管周向均匀受热工况进行了比较。结果表明,在螺旋管外壁面“外半周绝热、内半周受热”情况下管内流动沸腾换热系数值最大,而管外壁面“内半周绝热、外半周受热”情况下最小。 相似文献
16.
对环形通道内低Pe数(20~70)的高温(300~700℃)液钠在由非旺盛湍流转变成旺盛湍流区内(Re=4000~17500)的传热进行了实验研究,并对正压下液钠初始沸腾壁面过热度进行了理论分析与实验研究.结果表明,所提供的计算关系式与实验数据吻合良好.实验采用的环管内径为6mm,外径为10mm,通道外壁绝热,内壁用高热流密度电加热元件加热. 相似文献
17.
G. C. Mustakas W. J. Albrecht J. E. McGhee L. T. Black G. N. Bookwalter E. L. Griffin Jr. 《Journal of the American Oil Chemists' Society》1969,46(11):623-626
Oxidation of soybean lipids catalyzed by lipoxidase was prevented by heat treatment of soybean meats, which were then ground
to give a full-fat soy flour free of rancid odor and flavors. Our previous studies showed that lipids in cracked, dehulled,
soybeans rapidly oxidized after the lipoxidase system was activated by increasing moisture content to 20%. A series of experiments
are reported in which various heat treatments were evaluated for effectiveness of lipoxidase deactivation. Dry heat to 212
F, steaming, or both, deactivated lipoxidase to give flours that had low values of peroxide, conjugated diene and free fatty
acid and had good flavors after 2 years’ storage. Wet heat alone was also an effective treatment, whereas wet heat preceded
by dry heat at 180 F gave poor flavor stability after 2 years. Gas liquid chromatography studies gave evidence that the rapid
formation of volatiles in full-fat soy flours was catalyzed by an enzyme system. A 10 member taste panel was able to detect
significant flavor and odor differences between oxidized and nonoxidized samples.
Presented at the AOCS Meeting, Chicago, October 1967.
No. Utiliz. Res. Dev. Div., ARS, USDA. 相似文献
18.
B. D. Brown L. S. Wei M. P. Steinberg R. Villota 《Journal of the American Oil Chemists' Society》1982,59(2):88-92
The objective was to develop a procedure for inactivating lipoxy-genase in soybean cotyledons without losing protein solubility.
The approach was to moisten cotyledons to one of 2 levels in soft water or carbonate buffers, steam for a short time, hold
for a definite period at a known temperature, cool and analyze for enzyme activity and protein solubility. Temperature dependence
of both inactivation and insolubilization kinetics was determined. Increasing temperature of steaming and holding favored
our objective. At 16.3% moisture, the pH 9.8 buffer was beneficial but the pH 10.8 buffer was not. The holding period was
not beneficial compared to steaming alone. Recommended conditions were adjustment of cotyledon moisture to 16.3% with pH 9.8
buffer and then heating in steam for about 10 sec; at temperatures of 91 C and above, 99% of the lipoxygenase could be inactivated
with retention of over 70% protein solubility. The effect of buffers on kinetics of heat inactivation and insolubilization
appeared to be related to the states of hydration water, i.e., the presence of solute water at the higher moisture content. 相似文献
19.
The soybean extract that was dialyzed against distilled and deionized water and adjusted to pH 7.5 (dialyzed soybean extract;
d-SE) gave a transparent liquid after heating. The heated d-SE had less beany flavor and formed a translucent gel by heating
again with 0.2 M NaCl. Gelation occurred at a lower protein concentration with NaCl than that of the original soybean extract.
The dynamic viscoelasticity showed that the translucent gel from the heated d-SE was melted and gelled by the repetition of
heating and cooling, indicating reversible gelsol transition. Cryoprecipitation could be avoided by the heating of d-SE. A
gel was formed at 30°C by incubation of d-SE with NaCl. These properties of soybean extract may offer new applications as
a food ingredient. 相似文献
20.
Oils from normal or low-linolenic acid (18:3) soybeans that lack lipoxygenase (LOX) 2 or LOX 2 plus LOX 3 activities were
evaluated for their stability during frying and for oxidative stability in bread cubes stored after frying. Soybean oils were
extracted by a pilot-plant system and were refined, bleached, and deodorized in the laboratory. Citric acid was added to oils
during the cool-down stage of deodorization. Two replications, separated at the point of conditioning, were evaluated for
each genotype. Each sample (250 g) was heated to 180±5°C in a minifryer. Bread cubes were fried at the beginning of heating
and after 20 h of heating. Heating of the oils was continued for 10 h each day for three consecutive days. Soybean oils with
low 18:3 contents were significantly (P ≤ 0.05) more stable, as measured by conjugated dienoic acids and polymer values, than were oils with normal 18:3 contents.
Low-LOX 2 or low-LOX 2 + 3 activity had no effect on peroxide values of soybean oils extracted from bread cubes. Sensory evaluation
did not differentiate between oils that contained low or high 18:3 amounts or among oils from beans that lacked different
LOX enzymes. 相似文献