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1.
The high density steam flash-explosion (HDSFE) was used to extract protein from soybean meal. Soybean meal samples were treated at 1.3 MPa and 1.8 MPa for 60 s, 120 s and 180 s, respectively. After HDSFE treatment at 1.8 MPa for 180 s, the extraction yield of protein was increased from 50.50% to 65.66% compared with untreated soybean meal. The emulsification properties and fat-binding capacity of soy protein isolate (SPI) extracted from soybean meal treated by HDSFE were all improved compared with SPI extracted from untreated soybean meal and white flakes. Molecular weight distribution analysis of SPI showed that after HDSFE treatment the peak with molecular weight about 504 kDa and 43.3 kDa disappeared and the peak with molecular weight about 669 kDa increased indicating protein aggregation. Gel electrophoresis showed that high molecular weight aggregates of protein have been formed by covalent bond. 相似文献
2.
Eleni P. Kalogianni Calliope Karastogiannidou Thodoris D. Karapantsios 《International Journal of Food Science & Technology》2010,45(4):765-775
This work investigates the effect of potato presence on the degradation of extra virgin olive oil (EVOO) during repeated frying. For this reason the performance of EVOO during frying was compared with its performance during heating at frying temperatures. In order to make meaningful comparisons the temperature profiles obtained during the frying experiments were replicated during the heating experiments by means of a high energy exchange rate cooling/heating system. The effects of potato‐to‐oil ratio (1/7 and 1/35 kgpotatoes/Loil) and number (N) of batches (N = 0, 1, 0, 20, 30, 40) were examined. EVOO was analysed using high performance size exclusion chromatography (HPSEC). It was found that polymerisation products increased linearly during frying and heating and that they were not affected by potatoes presence at low ratio. The effect of potato presence became statistically significant (yet not remarkable) at the high ratio. Decomposition products increased during frying whereas they decreased during heating. 相似文献
3.
Physicochemical properties and amylopectin chain profiles of cowpea,chickpea and yellow pea starches
Junrong Huang Henk A. Schols Jeroen J.G. van Soest Zhengyu Jin Ellen Sulmann Alphons G.J. Voragen 《Food chemistry》2007,101(4):1338-1345
Starches from cowpea and chickpea seeds were isolated and their properties were compared with those of commercial yellow pea starch. Amylose contents were 25.8%, 27.2%, and 31.2%, and the volume mean diameter of granules, determined in the dry state, were 15.5, 17.9, and 33.8 μm for cowpea, chickpea and yellow pea starches, respectively. All three legume starches showed a C-type X-ray diffraction pattern and two-stage swelling pattern. Amylopectin populations were isolated and the unit chain profiles were analyzed by HPLC after debranching with pullulanase. The degree of polymerization (DP) of short chain populations was about 6–50 and the populations of long chain had a DP of 50–80. Cowpea showed a lower weight ratio of short:long chains than chickpea and yellow pea starches. The larger portion of long side chains in cowpea amylopectin can be correlated with a higher gelatinization temperature, greater pasting peak and a slight difference in crystalline structure found for cowpea starch. Chickpea and yellow pea starches exhibited similarity in unit chain profile of amylopectin as well as in gelatinization temperature and pasting profile, while they differed in amylose content, particle size and syneresis. It is assumed that the chain length distribution of amylopectin has a large influence on starch properties. 相似文献
4.
Stefanie Christiaens Sandy Van Buggenhout Ken Houben Ilse Fraeye Ann M. Van Loey Marc E. Hendrickx 《Food research international (Ottawa, Ont.)》2011,44(6):1604-1612
To investigate the structure-function relationship of pectin during (pre)processing, broccoli samples (Brassica oleracea L. cultivar italica) were subjected to one of the following pretreatments: (i) low-temperature blanching (LTB), (ii) LTB in combination with Ca2+ infusion, (iii) high-pressure pretreatment (HP), (iv) HP in combination with Ca2+ infusion, or (v) no pretreatment (control sample), whether or not in combination with a thermal treatment of 15 min at 90 °C. The macroscopic attributes of broccoli were linked to the chemical structure of broccoli pectin. By enhancing the cross-linking of pectic polymers, both LTB and HP reduced the texture loss that occurred during thermal processing of broccoli. During these pretreatments, homogalacturonan was de-esterified by pectin methylesterase, which led to changes in pectin solubility. When LTB or HP was combined with Ca2+ infusion, changes in the structure of pectin occurred, however not always reflected at the macroscopic level. The degree of esterification of pectin in Ca2+-soaked broccoli samples was lower compared to non-Ca2+-soaked samples and, in addition, a higher amount of ionically cross-linked pectin was retrieved. 相似文献
5.
Antonietta?BaianoEmail author Tommaso?Gomes Carla?Severini 《Journal of the American Oil Chemists' Society》2005,82(10):759-765
The effects of adding mixtures of herbs such as garlic, laurel, and marjoram on selected chemical indices of olive oil from
canned dried tomatoes were studied for various storage periods of up to 1 yr. Conventional analytical indices measured included
acidity, PV, and p-anisidine value. Flavored samples showed kinetic constant values that were significantly (P=0.001) higher than unflavored ones, whereas oligopolymer and oxidized TG and DG contents were similar to or slightly higher
than in the unflavored samples compared with those with herbs. The addition of the mixture of herbs slowed polymerization
reactions but did not inhibit TG oxidation. Discrepancies between the results obtained by conventional analyses and high-performance
size-exclusion chromatography indicated that the former approaches were insufficient to determine oxidative degradation of
oil as a result of interferences from compounds in the food matrix. 相似文献
6.
Aung K. Htoon Surjani Uthayakumaran Udayasika Piyasiri Ingrid A.M. Appelqvist Amparo López-Rubio Elliot P. Gilbert Roger J. Mulder 《Food chemistry》2010
The enzyme-resistant starch (ERS) content in processed high amylose and regular maize starches has been studied, with and without acid dextrinisation. The physicochemical and structural characteristics of the starches were analysed using a variety of techniques. The increase in ERS in high amylose maize starch with dextrinisation was related to the formation of a critical molecular weight fraction (MW ∼ 20,000) that could rearrange structurally. Further dextrinisation reduced the processed starch MW to below where it could still form ERS. Regular maize starch containing less than 30% amylose did not increase its resistance to amylase digestibility with acid dextrinisation, probably due to impairment of amylose rearrangement by the numerous branched amylopectin chains. The ERS, which is likely to form during the enzyme-digestion process, is a linear molecule with a maximum degree of polymerisation (DP) of 30, irrespective of the starch source, processing conditions applied or type and amount of acid used. 相似文献
7.
An investigation was carried out to evaluate the use of High Performance Size-Exclusion Chromatography (HPSEC) of polar compounds of refined, mild deodorized, extra virgin olive oils as well as of their blends, in attempting to reveal significant differences in the amounts of the substance classes constituting polar compounds among these oils. Two sets of blends were prepared by mixing an extra virgin olive oil with both refined and mild deodorized olive oils in increasing amounts. The obtained data highlighted that the triacylglycerol oligopolymers were absent or present in traces in the extra virgin olive oil, while their mean amount was equal to 0.04 g/100 g and 0.72 g/100 g in mild deodorized and refined olive oils, respectively. Oxidized triacylglycerols and diacylglycerols were more abundant in mild deodorized oil and refined oil than in extra virgin olive oil. The Factorial Discriminant Analysis of the data showed that the HPSEC analysis could reveal the presence of refined/mild deodorized oils in extra virgin olive oils. In particular, the classification functions obtained allowed designation of mixtures containing at least 30 g/100 g of mild deodorized oil and all those containing refined olive oil as deodorized oil, therefore as oils subjected to at least a mild refining treatment. 相似文献
8.
F. J. Sánchez-Muniz C. Cuesta C. Garrido-Polonio 《Journal of the American Oil Chemists' Society》1993,70(3):235-240
The alterations of a sunflower oil were evaluated by column, gas and high-performance size-exclusion chromatography after
being used for deep-fat frying fifteen repeated and discontinuous times. Polar compounds increased significantly (6.2 ± 0.3%
to 18.7 ± 0.8% in oil). Linoleic acid decreased (53.8 ± 0.2 to 48.1 ± 0.8 mg/100 mg oil) while oleic acid remained unaltered
after 15 fryings. Saturated fatty acids such as palmitic and stearic, also remained unaltered. Triglyceride polymers (0.1
± 0.0 to 2.4 ± 0.2 mg/100 mg oil), triglyceride dimers (1.0 ± 0.2 to 6.7 ± 0.3 mg/100 mg oil) and oxidized triglycerides (3.4
± 0.2 to 7.6 ± 0.3 mg/100 mg oil) increased significantly in the oil used 15 times to fry potatoes. These thermoxidative compounds
correlated well with the number of fryings (r=0.9864, r=0.9535 and r=0.9758, respectively). Diglyceride compounds remained
unaltered, while free fatty acids increased from 0.4 ± 0.0 to 0.6 ± 0.0 mg/100 mg oil. Both of these, which are characteristic
of hydrolytic alteration, did not correlate significantly (r=0.5985 and r=0.4261, respectively) with the number of fryings.
These data suggest that a thermoxidative process, rather than a hydrolytic one, took place in this study. 相似文献
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10.
ABSTRACT: We studied 26 margarines, 13 from hydrogenated fats and 13 from fractionated or interesterified fats, by using (1) traditional routine analyses, (2) silica gel column chromatography to separate the polar compounds, (3) high-performance size-exclusion chromatography for the qualitative and quantitative determination of the single classes of substances constituting the polar compounds, and (4) gas chromatography to determine the fatty acid composition and the trans isomers. The margarines prepared from hydrogenated fats showed significantly higher mean contents of both triglyceride oligopolymers ( P < 0.05) and trans isomers ( P < 0.001). Margarines obtained from fractionated or interesterified fats showed significantly higher mean contents ( P < 0.05) of polyunsaturated fatty acids. 相似文献