Evaluation of two methods to determine the polyphenol content in raw and cooked beans and its effect on protein digestibility]

The polyphenolic compounds present in raw and cooked, and dried, with and without the cooking broth of common white, black and red beans (Phaseolus vulgaris) were measured by the Folin-Denis method for total polyphenols, and by the protein precipitation method of Hagerman-Butler, which measures their biological activity. The polyphenol content was measured during 20 consecutive days on the same sample, using three different extracts of volume from each sample. Statistical analysis of the results by the Folin-Denis method indicated that variability among the three aliquots was different for each bean color. A non-parametric analysis, however, indicated that the average in the three levels of concentration for beans of all colors, was the same. A similar analysis of the results by the Hagerman-Butler method demonstrated that variability and average values for the three aliquots were equal for black and red beans but not for white beans. The coefficient of variation was lower for the higher aliquot of the extract. A significant correlation (r = 0.72, P less than 0.05, n = 60) was found between the two methods for all beans using the larger aliquot of the extract. The correlation was highly significant (r = 0.84, P less than 0.05) when white bean values were eliminated. The polyphenolic content varied with seed color and the thermic process reduced their content, as measured by the two methods. The losses in polyphenolics as measured by the Folin-Denis in the cooked beans dried with broth, varied from 31.4 to 36.3%, and from 39.8 to 51.1% for the cooked bean flour dried without broth. The losses by the Hagerman-Butler method were from 25.0 to 93.5% in the cooked bean flours dried with cooking broth, and from 33.3 to 95.7% when dried without the broth. The higher losses were recorded for red beans. In vivo digestibility for cooked bean flours, dried and without broth, were 73.2, 69.6 and 64.5%, and 71.9, 71.9 and 68.8% for white, red and black beans, respectively. A negative correlation (r = -0.39) and significant (p less than 0.05) was found between polyphenolic content in the diet and in vivo protein digestibility.     

Culinary practices and consumption characteristics of common beans at the rural home level

A survey was carried out on housewives of rural bean-producing areas for the purpose of collecting information on bean selection procedures, culinary practices and bean consumption in rural homes from four departments of northeastern Guatemala. The study sample consisted of 10 families selected at random from each of 19 municipalities. The questionnaire used had been pretested in two rural communities not included in the study sample. As already shown by other INCAP surveys of this nature, it was found that all families consumed common black beans, and on rare occasions beans of different color or species. With respect to cooking practices, it was found that beans are not usually soaked prior to cooking, and that few housewives add salt at the beginning of cooking. Two fractions are usually obtained, the cooked beans and the cooking broth. Another finding was that beans are consumed in four preparations: cooked whole, strained and fried, ground and fried, and cooked and fried. Bean broth is consumed by both adults and children, and a thick broth is preferred since it is considered to be more nutritious and better tasting. Children begin to consume bean broth as early as two months of age, and beans at 14 months. The average amount of broth ingested was 62 g, and whole cooked beans, 70 g. Mothers surveyed indicated that broth was administered to children because: it was nutritious (56% of the mothers); in order to teach children how to eat (15%); or because of its taste (9%). Regarding the hard-to-cook phenomenon, 32% of the housewives indicated that storage time was responsible for it, while 17% attributed this condition to bad seeds, and 18% to sun-drying or inadequate postharvest practices and to their preparation for consumption. Although the survey confirmed the importance that common beans have in rural diets, the main finding was that the first bean food product fed to children is the bean-cooking liquor or broth, which on the average contains 8.52% of total solids and 1.48% protein.     

Evaluation of a device to measure the hardness of the bean grain (Phaseolus vulgaris) and its use in the determination of cooking time

A simple equipment named DUR-INCAP was developed to study the factors responsible for the hard-to-cook beans and for other purposes related to this problem. The instrument measures objectively the hardness of individual beans, expressing the result as gram-force. The document describes the equipment. As a first step in establishing the usefulness of the equipment, a study using four white, four black and four red-colored beans, purchased in the market, was undertaken. Likewise, a black bean (Tamazulapa) harvested in January, 1983, and stored for one year at 5 degrees and 25 degrees C, and the same cultivar harvested in January, 1984, were also used. All beans were cooked in boiling water (95 degrees C) at atmospheric pressure for 30, 60, 100, 140 and 180 min. At each cooking time, a sample was withdrawn and its hardness measured individually on 25 kernels, with the DUR-INCAP. With the help of experienced persons in cooking, the hardness at each cooking time was classified into soft cooked beans (less than 100 g-force), medium (between 100-200 g-force) and hard (above 200 g-force). Results were as follows: white and black beans reached softness at 140 min of cooking, with the exception of one black sample which required 180 min. Two of the four red beans required 180 min, and the other two, needed 40 additional min. The effects of storage time and temperature on hardness became evident in the study with the black bean Tamazulapa. The sample stored for one year at 25 degrees C needed 140 min cooking time, while the sample stored at 5 degrees C and the one harvested in January, 1984, required 100 min. These initial results suggest that the DUR-INCAP instrument may be useful for the study of the hard-to-cook bean problem; however, additional analyses are required.     

Effect of the seed coat on the hardening of common beans (Phaseolus vulgaris)

Samples of cotyledons and whole black beans (Phaseolus vulgaris), Tamazulapa variety were stored during six weeks at 37 degrees C and 90% relative humidity to establish chemical and physical changes which occur during storage, and to determine the role played by the seed coat in the hard-to-cook phenomenon. After the storage period, samples of whole beans were divided in two subsamples, with and without the seed coat. These two samples and the cotyledons were analyzed for cooking time, water absorption, dietary fiber, tannic acid, soluble pectins and phytic acid. Cooking time of the whole beans increased from 99 to more than 480 minutes in the six-weeks period; for the cotyledons this value increased from 45 to 111 minutes. Cooking time of the dehulled bean, stored as whole bean, increased from 45 to 111 minutes. Cooking time of the dehulled bean, stored as whole bean, increased from 45 to 103 minutes. Water absorption in the whole beans and the cotyledons decreased, although in the cotyledons it was higher, due perhaps to the great absorption capacity to the seed coat. No changes were observed in the dietary fiber content of the cotyledons nor in the beans dehulled after storage. However, in the whole grains neutro-detergent fiber decreased, while acid detergent fiber, cellulose and lignin did not present significant changes. On the other hand, soluble pectates decreased in the whole bean and in the cotyledons; nevertheless the tannin content (as tannic acid) decreased only in the whole beans (from 3.28 to 1.64 mg/g). The data obtained suggest that the seed coat plays a significant role in the hard-to-cook process of hardening of the bean, before and during storage.     

水洗处理赤泥初步脱碱

赤泥是氧化铝冶炼工业生产过程中排放的固体废弃物,是一种严重的碱性污染源。实验采用不同温度（20、55、75、95 ℃）的水分别对强碱性赤泥进行洗涤。结果表明,首次洗涤所得洗涤液的质量浓度较高,6次洗涤液的平均质量浓度在2.44~2.72 g/L,其中冷水洗涤赤泥所得的溶液质量浓度最高。每次洗涤得到的洗涤液的pH变化不大。不同温度的水洗涤赤泥,回收碱的效率相差不大,前3次洗涤碱的回收量占总量的70%以上。其中,冷水洗涤赤泥回收碱的质量最多。经过6次洗涤后,每克赤泥中最终回收的氢氧化钠的质量最高达8.18 mg。     

热泵干燥可可豆品质的研究

本文主要针对热泵干燥在恒温和分段变温情况下对马来西亚可可豆品质的提高进行了研究。可可豆品质与热风干燥条件下的可可豆以及加纳可可豆和市售可可豆样本（马来西亚和印度尼西亚）进行比较。总体而雷,品质评估表明热泵干燥的可可豆品质比市售样品有明显的改善。就酸性程度和较高的褐变程度而雷,由逐步升温干燥所得的可可豆品质较高。热泵干燥样品的风味与加纳样品相当,优于市售样品。经逐步升温干燥制得的可可豆样品香味最浓,而且酸度、苦味和涩味适中。研究表明,使用热泵干燥对提高可可加工中可可豆的品质是可行的。     

Synthesis,Ion Exchange Properties,and Applications of Amorphous Cerium(III) Tungstosilicate

Abstract

A novel hetropolyacid-based cation exchanger cerium(III) tungstosilicate was synthesized in amorphous form by mixing tungstosilisic acid (TSA) solutions to cerium(III) nitrate solutions at different Ce:TSA ratios. The materials were precipitated from the liquid phase by raising the pH of the solutions using sodium hydroxide. The produced ion exchange powders were characterized using powder X-ray diffractometry, thermogravimetry, infrared spectrometry, inductively coupled plasma and atomic absorption elemental analysis. The materials which were dried at 50°C were found to be stable in water, dilute acids, alkaline solutions, and high temperature up to 1000°C. The Ion exchange properties of the synthesized samples were studied by measuring the distribution coefficients (K_d) for 29 metal ions in demineralized water and nitric acid media. On the basis of K_d values, some quantitative separations such as Co²⁺-Pb²⁺, Cr³⁺-Zr⁴⁺, and Mo⁶⁺- W⁶⁺ are achieved on their columns.     

Effect of solution pH on crack initiation and propagation in glass‐polyester pipes subjected to impact

The objective of this study was the determination of the influence of alkaline and acidic solutions on the impact properties of glass‐polyester composite pipes. First, the impact test was performed on virgin samples (without the influence of any liquid) to obtain knowledge about the original material properties. Subsequently, the specimens were soaked in water and in alkaline and acidic solutions: sodium hydroxide, ammonium hydroxide, phosphoric acid, and nitric acid. The specimens were left in each liquid for 3, 10, 30, and 60 days at room temperature. The impact toughness and the crack initiation and propagation energies were recorded for all samples. A comparison of the results was made based on the pH values of the aggressive media, as well as based on the original impact properties and number of days of treatment. This way, the service life of pipes for transport of theexamined solutions could be predicted. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

γ-Fe_2O_3磁粉的包钴工艺研究

对自制γ－Ｆｅ２Ｏ３磁粉的包钴工艺进行了详尽研究，并给出了最佳工艺条件。在４０Ｌ反应釜中进行扩大试验，制得矫顽力高、比饱和磁化强度大且性能稳定的包钴磁粉     

Effect of Sodium Hydroxide and Other Salts on Gossypol Content of Cottonseed Meal and Oil

Egyptian cottonseed meats used for oil production were obtained from one of the factories dealt with oil production in Egypt. The meats were cooked with some salts by using paraffin oil bath prior to oil extraction. The study revealed that different volumes of sodium hydroxide solutions of various concentrations when added to cottonseed meats before cooking greatly reduced the free gossypol content and the total gossypol of meals and oils by 28.3 to 92.9 and 17.9 to 100%, respectively. The extent of reduction depend mainly on the volume of the alkaline solution rather than on its concentration. The oil had a low free fatty acids content (0.33%) due to the alkali treatment. Cooking cottonseed meats with 1.85% calcium hydroxide and 0.5% ferrous sulphate solutions, reduced the gossypol content of the crude oil by 91%. The oil had colour of 9 red units, and free fatty acids content of 0.59%. This treatment completely diminshed the free gossypol content of meal. The crude protein content of the meals was decreased by 6 to 7%. This may be attributed to the loss of nitrogen due to the cooking by using the paraffin oil bath.     

Effects of the surface treatments of lignocellulosic fibers on their debonding stress

This paper presents some results on the surface treatments given to natural fibers, namely coir, banana, and sisal fibers, using γ-methacryloxypropyltrimethoxysilane (MEMO), y-aminopropyltriethoxysilane (AMEO), sodium alginate (NaAl), and sodium hydroxide (NaOH) solutions. The cleaned, washed, and dried fibers were dipped in these solutions separately for a given time and dried. Treated and untreated fibers were tested for strength properties including debonding stress, and structural analysis of the fibers was carried out. It was found that a 3-11% increase in debonding stress was observed for all the treated fibers; and about 30% increase in the ultimate tensile strength (UTS), 9% in initial modulus for silane-treated coir, and only 18% increase in UTS for NaAl-treated coir and sisal fibers were also observed. No significant improvement was observed in the case of surface-treated banana fibers.     

Characterization of Post-Consumer PET after Removal of the Original Surface: Influence of Raw Material

Post-consumer cooking oil and soft drink PET bottles (PET_oil and PET_{soft drink}) were ground and washed only with water (conventional washing). The polymer was then chemically washed (10 min in an aqueous solution of sodium hydroxide 5 mol·L^?1 at 90°C) and rinsed. The materials before and after chemical washing were characterized by intrinsic viscosity, differential scanning calorimetry, thermogravimetry, elemental analysis, scanning electron microscopy with X-ray spectrum microanalysis, and gas chromatography coupled to mass spectrometry. The results indicated that conventionally washed PET_oil is the material that most differs among the four tested ones, and that the other three are more similar to each other and to what is expected for pure PET. For example, the composition of PET_oil washed only in water contained 30 volatile organic compounds, 5 nonvolatile compounds, and 7 metals, while PET_{soft drink} washed conventionally and chemically contained 5 volatile organic compounds and no metal or nonvolatile organic compounds.     

三唑磷在水中消解和残留动态研究

研究了三唑磷在水中的残留测定方法及三唑磷在pH 5、pH 7、pH 9水中的消解动态。样品以正己烷提取,经无水硫酸钠干燥后用气相色谱(带FPD检测器)测定,0.1~20 g/ml的平均回收率为81.39%~ 95.38%。三唑磷在水中的降解率与水的pH有关,三唑磷在碱性水中降解较快(84.99%),在酸性水中降解较慢(61.43%);其在pH 5、pH 7、pH 9水中的半衰期分别为20.8、13.7、10.7d。     

Characterization of the nutritional potential of tepari bean (Phaseolus acutifolius) grown in Mexico

The chemical, physical, antiphysiological and biological quality of the protein of three varieties (white, brown and black) of tepary bean (Phaseolus acutifolius) were studied. Its proximate composition was determined, as well as water absorption, hardness of the seed, tannin content, trypsin inhibitors and lectins. Beans were also submitted to differential scanning calorimetry of the starch. The biological quality of its proteins was also established, based on the protein efficiency ratio (PER) and protein apparent digestibility. It was found that the protein content of the bean was high (25%). The white variety had the highest water absorption and the lowest hardness of the seed when compared with the other varieties (p less than 0.05). The black variety had a lower starch gelatinization energy and a higher cooking time than the white and brown varieties. The tannin content of the three varieties was low, particularly in the white one. The trypsin inhibitor and lectin content were relatively high in the raw beans, but disappeared almost totally during cooking. The biological quality of the tepari proteins was higher than that of the common bean cultivated under the same conditions, More evidently so in the white bean (PER = 1.48 as compared to 1.23 in pinto bean). It can be concluded that the tepary bean is a potentially good protein source and has also a great potential ad donor of genes for the obtention of better bean varieties from the culinary, nutritional and toxicological points of view.     

Effect of reheating on iron availability and the protein nutritive value of cooked black bean (Phaseolus vulgaris)]

In Guatemala, at the rural level, beans are prepared for family consumption every two days. Beans are cooked again every 12 hours for 15 minutes prior to their consumption. Due to the adverse effect that the process causes on nutritive value, the present study evaluated the method and preparation practice of beans on protein value; tannin and soluble and ionizable iron content. As to the effect of re-cooking on protein level, findings revealed that there were no significant statistical effects on net protein ratio (NPR) or in protein efficiency ratio (PER) and number of bean cooking. Nevertheless, a constant effect in quality in the first and second cooking procedure was detected. The second cooking gave a similar value as the first. Also, the first and second heating reduced protein digestibility, but the third gave a value similar to the initial one. No changes were observed in the digestibility of dry matter. Relatively high amounts of protein were found in the cooking broth, which was not affected by the number of heating. It was also found that the bean broth contained high levels of tannins in the initial heating, decreasing later significantly. The same was observed in the cooked beans alone and in beans with their broth. With respect to iron, findings showed a relatively high transference of beans to broth, in total iron as well as in soluble, ionizable and insoluble iron. No changes were observed in whole beans without broth caused by number of heatings, on total, soluble or ionizable iron. In beans with their broth, a similar effect was observed, although a slight increase in insoluble iron was detected at the end of heating. A decrease in soluble and insoluble iron was observed in broth with number of heatings. Correlations were calculated among the parameters studied, which suggested an effect of tannins on the bioavailability of iron caused by tannins.     

Soybeans as an extender of common beans

Soybeans were used as extenders of common beans in the form of whole beans and precooked, powdered form. Mixtures containing 20, 25, 30, 35, 40, 45 and 50% soybeans were studied. Sensory evaluations (preference tests) showed no preference for mixtures containing up to 50% soybeans over 100% common beans. On the other hand, nutritional differences were detected between common beans and mixtures with more than 20% soybean. The mixture with 50% common beans and 50% soybeans contained 27.9% crude protein, 13.2% lipids and 47.2% carbohydrate. The amino acid composition was improved particularly by increasing cystine from 0.6 to 1.2% of the protein and methionine from 0.7 to 1.2%. The protein efficiency ration (PER) values fo the 50:50 mixture for rats was 1.6 compared to 1.0 for the common bean. Acceptability of the 50:50 mixture in different institutional trials did not differ in consumption from that of common beans and no sign of physiological disturbance was observed. When the mixture was precooked, dried and ground to a powder, it served as an excellent base for an instant soup. The formulation containing 80% of the 50:50 mixture, 10% corn starch and seasonings had (%) 21.3 protein, 10.8 lipid, 5.3 crude fiber and 51.9 carbohydrate with total metabolizable energy of 390 Kcal/100 g and an NDP Cal%=12. The hydration capacity of the 50:50 mixture was 162 g water/100 g mixture whereas that of the soup with all ingredients added was 205 g water/100 g soup. The acceptability as well as the storage stability of the soup was good.     

Effects of traditional cooking on antinutritional factors of the black beans (Phaseolus vulgaris) of Costa Rica]

Trypsin inhibitors, alfa amylase inhibitors and hemagglutinins were determined in black beans (P. vulgaris) produced in Costa Rica. The effect of the traditional cooking on such antinutritional factors was also studied. The antinutritional factors were analyzed spectrophotometrically in the raw beans, as well as after several cooking periods of time. The results showed that alfa-amylase inhibitors were the most thermoresistant. After 30 min of cooking time there was a 33% of activity left from the initial activity of the raw beans. Approximately 80% of the antitryptic activity was destroyed at 9 min of cooking time. After 10 min of cooking time, only 1% of hemagglutinin activity was present.     

Nixtamalization cooking characteristics of 11 maize varieties

In the present study, 11 maize varieties were analyzed for their nixtamalization cooking quality. The 11 varieties were grown in the same locality and in the same year. The samples were evaluated for their physical characteristics, such as moisture content averaging 13.3%, average 1000 kernel weight (312.5 g), grain hardness through density (1.28 g/ml) and percent floaters (9.5%). These data indicated that all maize varieties had a hard endosperm which is recommended for the nixtamalization cooking process. The 11 varieties were formed on the average by 5.7% seed coat, 11.5% germ and 82.8% endosperm. The low seed coat content suggest a low solids loss during processing. Cooking quality evaluation was done by applying a standard lime cooking procedure to all varieties. An average solid loss of 3.2% was measured, with 0.8% of seed coat still attached to the endosperm. Water absorption at the end of cooking was 40.8% without soaking and 46.9% at the end of soaking. Nixtamal moisture was 47.9% after soaking and only 41.5% at the end of cooking. Cooking time with soaking for 50% moisture in the grain varied from 69 to 122 minutes at 1500 meters over sea level. The cooked grain was dried with hot air and ground however, the particle size obtained was not as that in commercial nixtamalized maize flour. However, the cooking quality parameters to make dough and tortillas were acceptable, with a penetration index of hydrated flour of 178.6 mm, pH 7.97, water absorption index (WAI) of 3.23 g gel/g flour and 4.11% water solubility index (WSI). All flours from the 11 varieties of maize gave acceptable tortillas as evaluated by physical characteristics and sensory quality. However of the 11 varieties 7 including the control were superior for nixtamalization cooking quality.     

氟硅酸制备高质量纳米白炭黑及F-溶液研究

以氟硅酸为硅源、氨水为氨解剂,制备合成了高质量的纳米白炭黑及高浓度氟离子溶液。考察了反应温度、加料方式、陈化时间及洗涤条件等因素对合成白炭黑性能的影响。确定了最佳工艺条件：在40 ℃下,分8次向氟硅酸中快速倾入氨解所需的氨水,直至体系的pH为8~9,陈化1 h,抽滤、水洗后再用少量乙醇润洗,抽滤、放置挥发后再在110 ℃下干燥2 h。所得白炭黑的粒度为89 nm 和322 nm,二氧化硅质量分数大于93%,比表面积大于 200 m2/g。所得溶液中氟离子的质量浓度可达90 g/L以上,有利于综合利用。