Obtaining macaroni-type spaghetti from a mixture of wheat flour and corn flour]

Pasta products were formulated using 10, 20, 30, 40 and 50% substitution of wheat flour with pre-gelatinized corn flour. Products were submitted to evaluation tests by comparing their main characteristics with those of the pattern, such as humidity, cooking time, water absorption, solubility in cooking water, texture, color, appearance and yield. The products obtained were economically available with good acceptability in relation to color, appearance and other characteristics evaluated.     

The structural analysis of wheat flour glycerolipids

The compositions of the fatty acids in the 1, 2 and 3 positions of the principal glycerolipids and their various stereoisomers were determined. Fatty acids in the 1 and 3 positions of triglycerides were similar in composition and less unsaturated than those in the 2 position. Fatty acids in the 1,2-, 1,3- and 2,3-diglycerides were distributed in a pattern which indicated isomerization ofsn-1,2-diacylglycerol. Lysophosphatidyl choline (the principal monoacyl lipid) consisted of about 80% 1-acyl and 20% 2-acyl isomers. The fatty acid compositions indicated that most of the 2-lysophosphatidyl choline was formed by isomerization of 1-lysophosphatidyl choline. Most of the digly cerides and lysophosphatidyl choline were synthesized in the ripening wheat grain. However a small proportion of these partial glycerides and all of the other minor partial glycerides (monoglycerides, digalactosyl monoglycerides) appeared to be the result of limited lipolysis of the corresponding diacyl lipids in the wheat or in the freshly-milled flour. Fatty acids in the 2 position of all the fully acylated glycerides were very similar in composition, but there were considerable differences in the 1 position fatty acids.     

Porous alumina ceramics prepared with wheat flour

It is shown that wheat flour can be used as a pore-forming and body-forming agent in ceramic technology. In contrast to pure native starch, however, the pores do not result from the swelling starch granules alone but are mainly due to protein-assisted foaming. Therefore the porosity is significantly higher and the pore size larger than that resulting from the starch granules alone, and the wet milling time applied for homogenizing the ceramic suspensions becomes the most critical process parameter. Alumina suspensions with 70 wt.% alumina and 20–30 vol.% wheat flour with different initial particle size (fine grade and semolina, respectively) have been prepared using milling times of up to 8 h. Porosities of up to approx. 60% can be achieved with only 20 vol.% of flour or semolina after 8 h of milling time, with the cell sizes (diameters of pore cavities resulting from foam bubbles) being essentially independent of the milling time (median diameters of 120–240 μm). Effective pore throat sizes (i.e. diameters of cell windows or channels between cells), measured via mercury porosimetry, are 1–2 μm for short milling times (2–3 h), but for long milling times (8 h) they change by more than one order of magnitude to median sizes of 20–30 μm, closely corresponding to the median size of wheat starch granules (approx. 20 μm).     

Combination of thin layer chromatography and gas chromatography in the analysis on a microgram scale of lipids from wheat flour and wheat flour doughs

Lipids were extacted on a microgram scale from 3 to 6 mg flour or from freeze-dried dough by percolation. The impure extract was separated into 12 nonpolar and 14 polar lipids by TLC. Then the fatty acid composition of most of these lipids was determined by gas chromatography. The microscale method renders possible qualitative and quantitative determination of the composition of the lipids in minute quantities of flour and dough. The selectivity of different extraction solvents was studied. In both flour and dough the fatty acid composition of a given component is identical in the free and bound lipid fractions. In dough, the quantity of free lipids is less than in flour; the extent of the decrease depends on the atmosphere in which it is mixed. During mixing, the carotenoid pigments, α-monoglycerides and the free linoleic acid and linolenic acid are oxidized. Oxidation is apparently a function of the concentration of oxygen and of lipoxidase.     

面粉中过氧化苯甲酰的检测方法研究

综述了面粉添加剂过氧化苯甲酰(BPO)常用的测定方法。目前BPO的检测方法主要包括化学分析法和仪器分析法,其中仪器法最常用,包括气相色谱法、液相色谱法、分光光度法、离子色谱法、电化学法及化学发光法等,其中以液相色谱法最具发展前景、应用最为广泛。     

The Composition and Properties of Purified Rapeseed Lecithins

The chemical and physical parameters of various quality grade rapeseed lecithins obtained from raw lecithin and from lecithin wet gum were evaluated. The chemical composition, fatty acids and metals contents, acid, peroxide and iodine values were determined. From the data it could be suggested, that the purified rapeseed lecithins obtained from 00-varieties, especially prepared directly from rapeseed wet gum are the interesting and valuable material for use in pharmacy, food industry and cosmetics.     

Preparation of cookies with a flour mixture of wheat and green plantain

With the purpose of diversifying the use of green plantain flour, a functional evaluation was performed by substituting 7% of chocolate cookie wheat flour by dehydrated green plantain flour; thus allowing to obtain a product with good physical and organoleptic qualities, as well as a better nutritional quality, as for dietary fibre and resistant starch. As a result of the use of this dehydrated green plantain flour (G-HT/HPV), the values of some chemical components increased significantly (P 0.05 Pound) in comparison to the standard cookies (GP): ash (2.46 to 2.69%), proteins (8.93 to 9.69%), dietary fiber (4.97 to 5.40%), resistant starch (0.19 to 0.23%) and total sugar (25.26 to 30.55). The G-HT/HPV complies with the industrial requirements as for moisture (2.7300%), ph (8.43), aw (0.205) and color (L = 31.78; a = 7.95 and b = 10.51). Besides, thanks to the use of G-HT/HPV the flours scattering during the kneaded process was diminished, thus reducing the cookie diameter and increasing the resistance to breaking (1.48 to 2.06 Kgf), in comparison to the GP. While evaluating the shelf life for G-HT/HPV, it was demonstrated that was affected by moisture, pH, aw and acidity after the first month of storage. In the preference comparison test between the G-HT/HPV and a trademark cookie (GC), no significant differences were founded. Both were accepted and qualified between good and very good, as for sensorial features like colour, fragrance and taste. However, significant differences were detected in relation to texture, and they were corroborated in the texture profile analysis. In this test the panel staff, while evaluating both types of cookies demonstrated that there are 8 features that can be used to describe them: firm, crumble, crisp, mealy, soft, lumpy, particle size and chewy.     

Enzymatic oxidation of linolenic acid in aqueous wheat flour suspensions

Linolenic acid oxidation by the enzyme lipoxygenase in an aqueous wheat flour suspension does not lead to accumulation of linolenic acid hydroperoxides but immediately to secondary oxidation products. The 3 most important products among these were identified as 9-hydroxy-trans-10,cis-12,cis-15-octadecatrienoic acid, 9-hydroxy-10-oxo,cis-12,cis-15-octadecadienoic acid, and 9,12,13-trihydroxy-trans-10,cis-15-octadecadienoic acid.     

Emulsifying Properties of Different Modified Sunflower Lecithins

Lecithins are a mixture of acetone-insoluble phospholipids and other minor substances (triglycerides, carbohydrates, etc.). The most commonly processes used for lecithin modification are: fractionation by deoiling to separate oil from phospholipids, fractionation with solvents to produce fractions enriched in specific phospholipids, and introduction of enzymatic and chemical changes in phospholipid molecules. The aim of this work was to evaluate the emulsifying properties of different modified sunflower lecithins in oil-in-water (O/W) emulsions. In this study, five modified sunflower lecithins were assessed, which were obtained by deoiling (deoiled lecithin), fractionation with absolute ethanol (PC and PI enriched fractions), and enzymatic hydrolysis with phospholipase A₂ from pancreatic porcine and microbial sources (hydrolyzed lecithins). Modified lecithins were applied as an emulsifying agent in O/W emulsions (30:70 wt/wt), ranging 0.1–2.0% (wt/wt). Stability of different emulsions was evaluated through the evolution of backscattering profiles (%BS), particle size distribution, and mean particle diameters (D [3, 4], D [3, 2]). PC enriched fraction and both hydrolyzed lecithins presented the best emulsifying properties against the main destabilization processes (creaming and coalescence) for the analyzed emulsions. These modified lecithins represent a good alternative for the production of new bioactive agents.     

Composition and distribution of individual molecular species of major glycolipids in wheat flour

The distribution of individual molecular species of the main wheat flour glycolipids, digalactosyldiglyceride (DGDG), monogalactosyldiglyceride (MGDG), digalactosylmonoglyceride (DGMG) and monogalactosylmonoglyceride (MGMG) has been investigated by reversed phase high-performance liquid chromatography of their benzoate derivatives after the respective galactosylglyceride classes were obtained by semi-preparative high-performance liquid chromatography. Combinations of linoleic acid at thesn-2 position with linoleic, oleic and palmitic acids at thesn-1 position predominated as major common molecular species of MGDG and DGDG. The pairs 16:0/20:4, 18:3/20:1, 18:0/18:3, 18:0/18:1 and 20:0/18:2 were determined only among MGDG molecular species. Five common molecular species containing 16:0, 18:0, 18:1, 18:2 and 18:3 fatty acids, respectively, were determined in MGMG and DGMG, with 18:2 being the most predominant form, and 18:1 (MGMG) and 16:0 (DGMG) as the next major fatty acids.     

Mapping the Chemical Variability of Vegetable Lecithins

There is an increasing interest in vegetable lecithins because of their broad usage in many food and cosmetic applications. In this research, the chemical variability of commercial lecithins from soy, sunflower and rapeseed were mapped. The acetone insoluble matter, total phospholipid content and their compositions were determined. Significant correlation coefficients were observed between phosphatidylcholine and phosphatidic acid (?0.84), phosphatidylethanolamine and phosphatidylinositol (?0.86), monounsaturated fatty acid and polyunsaturated fatty acid (?0.97). Principal component analysis was used to group the lecithins according to their sources. Rapeseed lecithin was found to be the most different product compared to soy and sunflower lecithin.     

Morphological and mechanical properties of dried skimmed milk and wheat flour mixtures during storage

Five mixtures of dried skimmed milk (DSM) and wheat flour (WF) were prepared and stored for 45 days at 20 °C and various relative humidities (RH) from 0% to 85%. Morphological properties, particle size distributions and mechanical properties were studied before and during storage. Scanning electronic microscopy (SEM) showed that samples stored at high RH (59-85%) agglomerated and formed a compact mass of powder due to caking phenomenon. The caking intensity increased with storage relative humidity and was expressed as the maximum force (F_max.) calculated from force/compression curves. DSM powders showed stick-slip behaviour during deformation and, moreover, this phenomenon increased with the DSM ratio in the mixture (up to 20 ± 1 N for 100% DSM) and disappeared with storage relative humidity.     

Positional Distribution of Fatty Acids in Oilseed Lecithins

Positional distribution of fatty acids in the lecithins (phosphatidyl choline) of cottonseed, groundnut, mustard and sesame seeds was studied. GLC analysis of the methyl esters showed the total lecithins to contain 60–80% of unsaturated fatty acids. The fatty acids liberated by phospholipase A hydrolysis consisted mainly of unsaturated (oleic and linoleic) acids. Estimates of lecithin classes in terms of saturated and unsaturated fatty acids in the α- and β-position, viz. SS, SU, US and UU, were made in these lecithins. The amount of disaturated (SS) lecithin was negligible and the content of US species was very low. Mustard, sesame, groundnut and cottonseed lecithins contained 27, 47, 56 and 60% of SU species respectively. The diunsaturated (UU) lecithin content was high in mustard (69%) and medium in sesame (49%), groundnut (43%) and cottonseed (31%).     

Development of bakery products for greater adult consumption based on wheat and rice flour

The present investigation was developed as a contribution to Guatemalan's elderly food and nutrition. Its main objective was to evaluate the chemical, nutritional and sensory quality of bread prepared from the partial substitution of wheat flour with rice flour. Wheat flour substitutions with rice flour in the order of 15, 20, 30, 40, 50 and 60% were evaluated. Differences with the control (100% wheat bread) were found during the process of preparation, as well as texture, volume, height, weight and specific volume. Important effects in dough handling were noted specifically in the 40, 50 and 60% rice bread. Thus, a sandy texture was found in breads of higher rice levels. The bread protein quality increased with the level of substitution; however the protein quality difference between the wheat bread and the bread with 60% rice flour did not achieve statistical significance. Based on a statistical analysis of the physical properties the bread with 30 and 40% rice flour was selected, and through a preference test between these last two, the 30% rice flour bread was selected as the sample best suited to the present study's purposes. This bread was not different to wheat bread in many nutritional parameters, although in others it showed to be superior. Each serving size of bread has a weight of 80 grams (2 slices) that contributes adequate quantity of calories, protein and sodium, although a little less dietary fiber than 100% wheat bread.     

高效液相色谱法测定小麦粉中增白剂过氧化苯甲酰

本文提出了用高效液相色谱分离和测定小麦粉中增白剂过氧化苯甲酰的新方法。用水为溶剂通过超声提取面粉中的过氧化苯甲酰,在酸性环境中用铁粉使之还原为苯甲酸,然后在中性环境下用高效液相色谱进行测定,具有良好的准确度和再现性。     

Optimized separation of nonpolar and polar lipid classes from wheat flour by solid-phase extraction

A method combining solid-phase extraction on prepacked silica and aminopropyl bonded-phase (Bond-Elut) columns has been developed for the separation of neutral lipids, glycolipids and phospholipids from wheat flour into individual classes in high yield and homogeneity. Chromatography on a single silica column (500 mg) with solvent combinations of increasing polarity resulted in complete separation of steryl esters, triglycerides, free fatty acids, 1,2-diglycerides, 1,3-diglycerides, monoglycerides, monogalactosylglycerides, digalactosylglycerides, phosphatidylcholine and lysophosphatidylcholine. Chromatography on an aminopropyl bonded-phase column (500 mg) with ternary mixtures of chloroform/methanol/ammonium hydroxide led to the proper separation of N-acyl-phosphatidylethanolamine and N-acyl-lysophosphatidylethanolamine, previously coeluted on the prepacked silica column. Cross contamination among phospholipid classes tested by normal-phase high-performance liquid chromatography was always less than 14%.