不同预处理对发酵酸豆乳品质及抗营养因子含量的影响

本文以大豆为研究对象,在浸泡温度为25℃、豆水比为1:4、浸泡时间16h的条件下,采用不同介质(水、0.45%柠檬酸溶液、0.45%碳酸氢钠溶液)浸泡及萌发等预处理后制备发酵酸豆乳,考察对酸豆乳抗营养因子变化及营养品质的影响。结果如下：以干豆榨取的豆乳作为对照组,酸豆乳中胰蛋白酶抑制剂的还原作用依次为发芽>碳酸氢钠>水>柠檬酸；植酸含量依次为发芽>柠檬酸>水>碳酸氢钠；单宁含量的降低作用依次是发芽>碳酸氢钠>柠檬酸>水。浸泡处理可有效降低酸豆乳中抗营养因子的含量,碳酸氢钠浸泡组去除抗营养因子效率最高,质量最好。此外,高温处理将胰蛋白酶抑制剂含量降低70%,植酸和单宁属于热不敏感因子,高温处理效果不够显著。因此,本研究最终确定的预处理条件为发芽,碳酸氢钠浸泡。     

Nutrients and antinutritional factors in faba beans as affected by processing

 The influence on the nutrients content (soluble sugars, starch, dietary fibre and calcium) and antinutritional factors (α-galactosides and phytic acid) of faba beans (Vicia faba, L. major) of soaking in different solutions (distilled water, citric acid, and sodium bicarbonate solutions), cooking the presoaked seeds, dry-heating and germination have been studied. Soaking brought about a decrease in starch, sucrose, fructose, α-galactoside, dietary fibre and calcium content. Glucose was detected in soaked faba beans and soaking did not modify the phytic acid content. Cooking the presoaked faba beans produced a slight decrease in starch, and caused a general drop in α-galactosides, dietary fibre, calcium and phytic acid, with the exception of seeds presoaked in sodium bicarbonate in which cooking did not cause any appreciable changes in comparison with the unprocessed faba beans. Germination caused a sharp reduction in α-galactoside and phytic acid content after 6 days, whilst starch and dietary fibre decreased slightly. Calcium, however, enjoyed a slight increment during germination which was related to the decrease in the content of hemicellulose and phytic acid. Dry-heating caused a noticeable reduction in all the nutrients and antinutritional factors investigated. Of all the treatments studied, germination appears to be the best processing method to obtain nutritive faba bean flour, since it caused a minor decrease in starch content (15% loss), the largest α-galactoside and phytic acid removal (94% and 45%, respectively) and provided an appreciable amount of dietary fibre. Received: 21 December 1997 / Revised version: 19 February 1998     

Effects of Processing on the Reduction of β-ODAP (β-N-Oxalyl-L-2,3-diaminopropionic acid) and Anti-Nutrients of Khesari Dhal,Lathyrus sativus

Effects of different processing techniques on the neurotoxin, β-ODAP (β- N -oxalyl-L-2,3-diaminopropionic acid), and the anti-nutritional compounds (phytate, polyphenols, trypsin and amylase inhibitors, and lectins) within four lines of Lathyrus sativus (high-, medium- and low-ODAP, and so-called ODAP-free) were investigated. Soaking of seeds in various media reduced the contents of these compounds to a varying and significant extent; losses were higher in freshly boiled water, alkaline and tamarind solutions than after soaking in drinking water. The highest losses in boiled water (65–70%) were observed for β-ODAP, followed by trypsin inhibitors (42–48%) and polyphenols (30–37%). Ordinary cooking and pressure cooking of pre-soaked seeds were found to be most effective in reducing the levels of all the natural toxicants examined, whilst fermentation and germination were more effective in destroying both of the enzyme inhibitors (amylase inhibitors by 69–71%; trypsin inhibitors by 65–66%) than either phytates or polyphenols. Lectins were not affected by most of these processes except by pressure cooking and fermentation. Dehusking of pre-soaked seeds significantly reduced β-ODAP levels, but this reduction was lower for the anti-nutrients. These findings and the high water solubility suggest that a simple and effective means of detoxifying Lathyrus by removing this neurotoxic amino acid may be practicable.     

Effect of domestic processing and cooking on the antinutrients of black gram

Domestic processing and cooking methods including soaking, ordinary and pressure cooking of soaked and unsoaked seeds, and sprouting significantly lowered phytic acid, saponin and polyphenol contents of black gram (Vigna mungo) seeds. Soaking for 18 h removed 28% of the phytic acid; extents of removal were higher with longer periods of soaking. Saporins andpolyphenols were relatively less affected. Loss of the antinutrients was greater when soaked instead of unsoaked seeds were cooked. Pressure cooking had a greater effect than ordinary cooking. Antinutrient concentrations declined following sprouting; the longer the period of germination the greater was the reduction. Phytic acid was reduced to a greater extent than polyphenols or saponins.     

Domestic processing effects on available carbohydrate content and starch digestibility of black grams (Vigna mungo) and chick peas (Cicer arietium)

Domestic processing effects on available carbohydrate contents and starch digestibility of black grams and chick peas were investigated. The food legumes were soaked in tap water and alkaline solution of sodium bicarbonate at 30 and 100 °C for 1–2 h before cooking under pressure. Total soluble sugars, reducing sugars and starch contents of black grams and chick peas were 9.64% and 9.83%, 0.78% and 0.83%, 43.0% and 44.3%, respectively. All these available carbohydrate contents of black grams and chick peas were reduced to various extents as a result of soaking and cooking. At 30 °C, 4.46% of total soluble sugars, 3.84% of reducing sugars and 6.86% of starch contents were reduced on soaking the black grams in tap water for 1 h. Available carbohydrate contents were further reduced when soaking time and temperature of the food legumes was increased before cooking. About 3.43–25.0% of total soluble sugars and 4.26–22.7% of starch contents were lost on soaking black grams and chick peas in tap water and sodium bicarbonate solution. Maximum amounts of total soluble sugars (28.5–59.6%) and starch contents (29.9–67.4%) were lost on cooking the water- and alkali-soaked food legumes. However, these losses were comparatively less with the water soaking process. Besides these losses, starch digestibilities of black grams and chick peas were markedly improved as a result of cooking. However, no appreciable improvement in the starch digestibility was observed after soaking these food legumes in water or alkaline solution.     

Micronization pretreatments for reducing the cooking time of lentils

For many grain and grain legume crops, a pretreatment step is often employed prior to processing to improve the quality of the final product. The pretreatment may be tempering, where a uniform specified moisture content in the grain is desired, or soaking, where moisture content is high and unevenly distributed. This study evaluated the effect of moisture contents and reagents as potential pretreatments for micronization (infrared heat treatment) of lentils, the objective being to reduce lentil cooking times. The texture of over-, under- and optimally cooked lentils was defined by sensory methods and by peak force values at 40% compression. As cooking time increased, sensory scores for hardness, chewiness and particle size decreased, as did peak force values. The peak force for optimally cooked lentils receiving no pretreatment was the control used to assess the effectiveness of a given pretreatment. The pretreatments studied were soaking of lentils, tempering of lentils to 20 or 40% moisture with water alone, and tempering to 20 or 40% moisture with solutions of various reagents: sodium salts of carbonate, bicarbonate, phosphate, tripolyphosphate and EDTA, and mixtures of citric and ascorbic acids. For tempering pretreatments, cooking time was reduced as moisture increased, but it was only at 40% moisture that added reagents were effective in reducing lentil cooking times. It was postulated that free water must be available in the cotyledon to allow reagents in the tempering water to reduce cooking time beyond that attainable with water alone. Potential reagents for tempering solutions used as successful micronization pretreatments were 2% sodium tripolyphosphate, mixtures of 1% citric and 2% ascorbic acid, and 150 ppm disodium EDTA. © 1998 SCI.     

大豆预处理方式对豆浆品质的影响

为了最大程度地降低抗营养因子含量,同时保证其品质优良,试验探究不同预处理方式及浸泡介质对豆浆中抗营养因子及其营养品质的影响。结果表明,在降低胰蛋白酶抑制因子活性方面,高温处理﹥萌发处理﹥浸泡处理,高温处理下的胰蛋白酶抑制因子活性仅为(3.12±0.70)TIU/mg,相对于未处理组降低了95.35%;3种处理方式下单宁含量均显著增高(P<0.05),萌发处理﹥高温处理﹥浸泡处理;在降低植酸方面,萌发处理﹥浸泡处理﹥高温处理,最低含量仅为(3.66±0.19)mg/mL;品质方面,浸泡方法为最优方法,保证了豆浆的高蛋白含量和低沉淀率。浸泡介质中,NaHCO3在某些条件下降低胰蛋白酶抑制因子的效果较好,同时较好地保持了豆浆品质;而柠檬酸在降低植酸含量上表现出色,但品质方面表现较差。综上,对豆浆进行预处理宜选择浸泡处理,在保持豆浆品质的同时,可以最大限度降低豆浆中抗营养因子含量。     

不同预处理方式对热风干燥黄花菜褐变及干燥特性的影响

本实验探究不同护色液（0.1 g/100 mL柠檬酸、0.2 g/100 mL柠檬酸、0.2 g/100 mL碳酸氢钠、1.0 g/100 mL氯化钠溶液,浸泡45 min）对烫漂（蒸汽和热水,处理2 min）处理后黄花菜成品褐变抑制及干燥特性的影响,对其干制品外观色泽、营养成分和微观结构进行表征,同时采用傅里叶变换红外光谱法比较不同预处理对其结构的影响,并通过主成分分析获取具有较高商品价值的黄花菜干燥预处理条件。结果表明,抑制褐变效果方面：蒸汽烫漂>热水烫漂;0.2 g/100 mL柠檬酸溶液>0.1 g/100 mL柠檬酸溶液>1.0 g/100 mL氯化钠溶液>0.2 g/100 mL碳酸氢钠溶液。干燥处理效果方面：采用0.2 g/100 mL柠檬酸溶液进行护色处理的黄花菜干燥速率最快且复水效果较好;综合考量,以蒸汽烫漂（2 min）+0.2 g/100 mL柠檬酸溶液浸泡（45 min）条件进行预处理后,黄花菜干制品的外观色泽、黄酮与多酚含量及微观结构等品质较佳。经主成分分析可知,多酚含量、5-羟甲基糠醛含量与色差、褐变度高度相关,咀嚼性与硬度相关性最高...     

不同预处理对家庭制豆浆抗营养因子含量的影响

目的:研究不同预处理对家庭制豆浆中抗营养因子含量的影响。方法:对大豆在室温和冷藏条件浸泡、干炒及发芽2d处理后制成豆浆,以与干豆制浆为对照,比较其单宁、植酸、皂苷和胰蛋白酶抑制剂的保存率。结果:发芽处理豆浆组分的单宁、植酸、皂苷、胰蛋白酶抑制剂的保存率分别为31.83%、27.28%,20.19%、12.89%;室温浸泡处理12h分别为34.56%、43.72%、32.10%和9.91%;干炒处理消除抗营养因子的效率不及发芽和浸泡处理,但与干豆制浆处理差异显著,各抗营养因子的保存率分别为64.05%、54.59%、28.78%、10.88%。结论:与干豆制浆相比,各处理均显著降低了豆浆中抗营养因素的保存率。其中发芽处理对于降低单宁和植酸的效果最显著,12h浸泡处理对降低胰蛋白酶抑制剂最为有效。     

Polyphenols and tannins in Indian pulses: Effect of soaking,germination and pressure cooking

Polyphenols and tannins have implications for health and nutrition. There is limited information on their content in pulses, raw or post-processing. We estimated the concentrations of polyphenols and tannins in different cultivars of four pulses commonly consumed in India – Phaseolus aureus, Cajanus cajan, Lens esculenta and Cicer arietinum – and examined the effects of domestic processing. Means and standard deviations were calculated and results were analyzed by ANOVA. There were significant differences (P < 0.001) in the polyphenol and tannin contents of cultivars of the same pulse, with the exception of the tannin contents of pressure-cooked red gram cultivars (P = 0.3103). Processing reduced the concentrations of polyphenols by 19–59% and of tannins by 22–59%. A trend was observed in the degree to which processing reduced polyphenol and tannin contents (germination > pressure-cooking > soaking). Soaking, germination and pressure-cooking proved to be effective household strategies to reduce the levels of polyphenols and tannins in pulse-based foods, thereby enhancing the bioavailability of pulse protein. There is a need to determine the extent to which the remaining polyphenols and tannins are rendered unavailable by these processing techniques.     

Effects of extrusion and conventional processing methods on protein and antinutritional factor contents in pea seeds

The effects of high temperature short time (HTST) treatment compared with other conventional processes on protein, phytic acid, condensed tannins, polyphenols, trypsin, chymotrypsin and α-amylase inhibitor activities and haemagglutinating activities in Renata, Solara and Ballet pea seeds were investigated. Ballet cultivar showed highest protein, phytic acid, tannin, polyphenol contents and trypsin and chymotrypsin inhibitory activities. All pea cultivars contained trypsin- and chymotrypsin-inhibiting activity and lectins but only Solara had α-amylase inhibitory activity. Under extrusion conditions (148°C, 25% moisture and 100 rpm) this thermal processing method was the most effective in condensed tannin, trypsin, chymotrypsin, α-amylase inhibitors and haemagglutinating activity reduction, without modifying protein content as occurs by dehulling, soaking and germination treatments. Trypsin and chymotrypsin inhibitors and haemagglutinating activities in peas were more readily abolished by extrusion treatment than was chymotrypsin inhibitory activity.     

Impact of pre-treatment (soaking or germination) on nutrient and anti-nutrient contents,cooking time and acceptability of cooked red dry bean (Phaseolus vulgaris L.) and chickpea (Cicer arietinum L.) grown in Ethiopia

Pulses are processed in diverse ways prior to consumption. Soaking and germination are among the most common traditional, household-level food processing strategies. This study was carried out to determine the effects of soaking, germination, cooking and their combinations on the contents of selected nutrients and anti-nutrients of red dry bean and chickpea. In addition, the effects of pre-treatment on cooking time and the acceptability of dishes prepared from red dry bean and chickpea were determined. The nutrient compositions (zinc, iron and calcium) of most soaked-cooked and germinated-cooked red dry bean and chickpea samples were not significantly different than those of respective controls. However, soaking and germination pre-treatments significantly lowered the phytate and tannin contents of the red dry bean and chickpea samples, with a few exceptions, and overall, polyphenol contents were lower after soaking-cooking than after germination-cooking. Most scores for sensory attributes of bean-based and chickpea-based dishes prepared from soaked or germinated samples were not significantly different than those of the controls. For most red dry bean and chickpea samples, longer germination times yielded superior results in terms of reductions in cooking time, tannin content, and phytate:zinc and phytate:iron molar ratio.     

豆浆中抗营养因子的去除方法

采用碱液浸泡、微波处理、加热处理、去皮等方法,对去除豆浆中抗营养因子的效果进行比较。其中,88℃恒温热处理10min可将豆浆中脂肪氧化酶活性降至常温下的14.20%,100℃恒温热处理20min可将豆浆中的胰蛋白酶抑制剂降低到9.96%。微波处理(2450MHz,800W)2min可以将脂肪氧化酶活性降至8.86%,处理8min可以将胰蛋白酶抑制剂活性降低到11.24%,处理4min即可将尿素酶活性降低至1%。相比于常规的热处理,微波处理可以更快速地破坏豆浆中的抗营养因子,缩短处理时间。此外,采用0.5%NaHCO3溶液浸泡、去皮等措施也可去除豆浆中的抗营养因子,可结合常规热处理、微波处理应用,以缩短加工时间。     

Effect of differential processing methods on L-Dopa and protein quality in velvet bean, an underutilized pulse

Different accessions of velvet bean were subjected to traditional and technological processing methods like soaking, germination, microwave cooking, dry heating and γ-irradiation with a view to assess the extent to which the L-Dopa gets reduced. Furthermore, the impact of certain processing methods on the levels of total protein and essential amino acid profiles was also assessed. The percentage of L-Dopa in the raw seeds ranging from 5.63 (Mundanthurai white-coloured) to 4.44 g/100 g DM (Mundanthurai black-coloured). The processes of germination (120 h) and soaking in Ca(OH)₂ solution effected significant reduction in the content of L-Dopa (i.e., from 34.8% to 58.4%; and 5.6% to 54.5%, respectively). On the contrary, dry heat treatment and microwave cooking appeared to be less effective in reducing the contents of the same. While, γ-irradiation at 10 kGy seemed to be more effective in reducing the L-Dopa than at 5 kGy. Soaking in calcium hydroxide, microwave cooking and γ-irradiation had little impact on the profiles of essential amino acids except cystine (which was completely deactivated) in both the accessions of Thachenmalai. Nonetheless, in Thachenmalai (black-coloured) accession upon soaking in calcium hydroxide, the levels of valine, phenylalanine, tyrosine, isoleucine and histidine were found to be comparable with FAO/WHO (1991) requirement pattern. To sum up, of the various processing methods employed in the present study, germination and soaking in calcium hydroxide were effected greater reduction in L-Dopa content and caused minimum effect on the profiles of essential amino acids of seed proteins.     

Dietary Fiber in Processed Lentils

Effect of soaking (distilled water, 0.1% citric acid (CA) and 0.07% sodium bicarbonate (SB) solutions), and cooking (distilled water) was studied on dietary fiber components of lentils. A high increase of protopectin, total pectic substances (PS), and dietary fiber (DF) was observed in soaked lentils (dry matter basis). Soaking in CA and in SB solutions led to an appreciable increase of hemicellulose (HMC) and neutral detergent fiber, but not in lentils soaked in water. Cooking the previously soaked lentils, reduced the amount of DF, due to a drastic loss of HMC, although cellulose and lignin increased. PS content of cooked lentils, previously soaked in CA and SB was still higher than in raw lentil.     

Content of phytic acid and HCl-extractability of calcium,phosphorus and iron as affected by various domestic processing and cooking methods

ICPL-87, the high yielding cultivar of pigeon pea (Cajanus cajan) released by ICRISAT (International Crop Research Institute for Semi-Arid Tropics), India was subjected to various domestic processing and cooking methods, i.e. soaking (6, 12, 18 h, 30°C), soaking (12 h) and dehulling, ordinary as well as pressure cooking and germination (24, 36 and 48 h, 30°C). The unprocessed seeds of this variety contained considerable amounts of phytic acid, (857 mg per 100 g). This was reduced significantly (P<0.05) by 6–28%, 30%, 4–32%, 4–36%, 35–45% in soaked, soaked-dehulled, ordinary as well as pressure cooked and germinated seeds, respectively. Except for soaking and dehulling, the remaining processing and cooking methods did not lower the contents of total calcium, phosphorus and iron. HCl-extractability of these dietary essential minerals, an index of their bioavailability, was enhanced significantly when the pigeon pea seeds were processed and cooked, possibly due to reduction in phytate content, which is known to chelate the minerals. A significant and negative correlation between the phytic acid and HCl-extractability of minerals further strengthens these findings.     

Changes in chemical composition,grain malting,starch and tannin contents and protein digestibility during germination of sorghum cultivars

Malting loss and changes in chemical composition, starch and tannin contents and in vitro protein digestibility (IVPD) were determined during germination of low (0.32%) and high (1.44%) tannin sorghum cultivars. For both cultivars, crude protein, fibre, fat and ash contents were slightly decreased after soaking and germination of the seeds. Malting loss was slightly increased for both cultivars and for all germination periods. Starch degradation was high for both cultivars. Depending on the soaking time about 56–66% and 98–99% tannin were lost during 72 h germination in low and high tannin cultivars, respectively. IVPD was markedly decreased in the low tannin cultivar and markedly increased in the high tannin one with the germination time. Soaking, on the other hand, was found to have a minor effect on IVPD. It is suggested that tannins are responsible for retarding the protein digestibility and starch degradation, especially in the high tannin cultivar.     

THE EFFECT OF PROCESSING ON THE TRYPSIN INHIBITOR, HEMAGGLUTININ, TANNIC ACID AND PHYTIC ACID CONTENTS OF SEEDS OF TEN COWPEA VARIETIES

Trypsin inhibitor (TI) and hemagglutinin activities, tannic acid and phytic acid contents were determined in ten varieties of cowpea. The different varieties were subjected to four processes; cooking, soaking, autoclaving and germination. TI and hemagglutinin activities were completely eliminated by cooking and autoclaving, while tannic acid and phytic acid contents were only partly affected. Cooking reduced tannic acid contents by 31.0–47.3%. Soaking for three days decreased TI activity by a mean of 31.2%, hemagglutinin activity by 19.0%, tannic acid by 13.4% and phytic acid by 24.4%. Maximum germination effects on TI and hemagglutinin activities were obtained in 'Westbreed' and 'Kano 1696' where percentage losses amounted to 57.2 and 57.6, respectively. The phytic acid contents of all varieties were greatly reduced by germination.     

Effects of processing and storage on walnut (Juglans regia L) tannins

Walnut tannins were maximally extracted with absolute methanol and an extraction time of 60 min. Storage (21 days at 25 °C) significantly reduced (20–40% reduction) the assayable tannin content in walnuts. The ranges of tannin content in freshly cracked inshell and shelled walnuts were respectively 372–1095 and 363–667 mg catechin equivalent per 100 g dry weight. The assayable tannin content in inshell and shelled walnuts was 10–20% higher when the particle size was reduced from 2‐ to 8‐mesh. Using 0.5 as compared to 2% (w/v) vanillin as colour development reagent yielded 15–20% higher assayable tannin contents. The assay colour development reached a maximum after 20 min of incubation at 25 °C. Roasting (204 °C for 5 min) caused a small (14%) but significant reduction in assayable tannins. Soaking in aqueous alkali solutions was more effective (44–100% reduction) than soaking in aqueous acid solutions (6–76% reduction) in decreasing the assayable tannin content in walnuts. Microwave heating in distilled deionised water resulted in 93–98% reduction in walnut assayable tannins. Blanching at 100 °C for 2 min was as effective as alkali soaking in significantly reducing the amount of extractable walnut tannins (98% reduction). The tannin content in blanched walnuts was positively related to astringency scores (r = 0.92). © 2001 Society of Chemical Industry     

Effect of alkaline pretreatment and cooking on protein fractions of a high-tannin sorghum cultivar

A high-tannin sorghum cultivar (Karamaka) was used to study the effect of soaking in distilled water or 0.05%, 0.10% and 0.20% NaOH for 8 h, and soaking in distilled water or NaOH followed by cooking, on proximate composition, tannin content and protein fractions. Results showed that soaking the sorghum grains in water or NaOH for 8 h caused a slight increase in crude protein, whilst the tannin content significantly (p ? 0.05) decreased. The highest drop in tannin content was observed after soaking sorghum in 0.20% NaOH for 8 h at ambient temperature. Combining soaking and cooking further lowered the tannin content of sorghum, with a maximum reduction of 83.9%. Soaking in NaOH and cooking caused significant (p ? 0.05) increases in the albumin and globulin fractions, accompanied by a significant reduction in the glutelin fraction. This readjustment of sorghum protein fractions would indicate improvement in the quality of sorghum proteins.