Contents and digestibility of carbohydrates of chickpea and black gram as affected by domestic processing and cooking

Starch digestibility (in vitro) and level of total soluble sugars, reducing sugars, non-reducing sugars and starch in cultivars of chickpea (Cicer arietinum), as well as black gram (Vigna mungo), varied significantly. The effects of different domestic processing and cooking methods on the contents of starch, sugars and starch digestibility (in vitro) of eight varieties of chickpea and four of black gram were investigated. Cooking, autoclaving and germination decreased the starch content and increased the level of total soluble sugars, reducing sugars, non-reducing sugars and starch digestibility of both the legumes. Soaking reduced the sugars considerably but starch only marginally. Autoclaving increased starch digestibility more than 4-fold and 5-fold in chickpea and black gram, respectively. Cooking and sprouting also improved starch digestibility appreciably.     

Changes in carbohydrate contents of germinating cowpea seeds

A decrease in the concentration of total carbohydrates was observed during 144 hours' germination of three cowpea varieties. However, whilst starch, raffinose, stachyose and verbascose levels decreased, the reducing sugars, including glucose and fructose, increased. Starch was the major carbohydrate and about 50% of it was hydrolysed after 144 hours' germination. Changes also occurred in the concentration of the unavailable carbohydrates. Lignin contents increased slightly while hemicelluloses and celluloses decreased. The above-mentioned changes, occurring during germination, appear to have a favourable effect on the nutritional value of cowpea varieties.     

Changes in the composition and carbohydrate constituents of okra (Abelmoschus esculentus, Linn.) with age

Changes which occurred in the proximate composition, concentrations of free sugars, high molecular weight carbohydrates (water-soluble polysaccharides, starch hemicellulose and cellulose) and lignin in four varieties of okra when harvested at different ages have been studied. Samples were collected from the field at 1, 4, 7 and 10 days after flowering. Crude protein, which initially ranged from 19·9 to 24·7 g/100 g DM, decreased with age whilst crude fibre, 12·5–16·7 g/100 g DM, increased with age. Ether extract varied between 1·60 and 2·19 g/100 g DM whilst ash was 8·00–8·59 g/100 g DM. Available carbohydrates (starch + sugars) ranged from 11·2 to 13·1 g/100 g DM whilst unavailable carbohydrates increased from 33·9–42·0 g/100 g DM to 51·9–59·7 g/100 g DM.Overall varietal differences were apparent for ethanol-soluble sugars and the structural carbohydrates while differences among the means due to age were significant (P < 0·05).     

马铃薯块茎干物质、淀粉及还原糖含量的检测及相关性分析

本文以来自全国13个省(14个地区)46个品种的马铃薯为实验材料,采用国家标准方法或国标方法稍有改动,检测马铃薯的干物质、还原糖和淀粉含量。再通过SPSS 20.0对不同样品中还原糖和淀粉含量差异的显著性进行了分析,并采用矩阵散点图、一元线性回归研究了干物质、还原糖和淀粉含量之间相关性。结果表明:马铃薯中干物质含量为15.43%~29.67%,还原糖含量为0.09%~1.84%,淀粉含量为9.11%~22.30%(均为湿基);大部分样品的还原糖含量差异都很显著(p0.05),淀粉含量差异也很显著(p0.05);通过矩阵散点图发现马铃薯中还原糖含量与干物质含量无相关性,与淀粉含量也无相关性;马铃薯中干物质含量和淀粉含量呈正相关,服从一元线性方程:y=9.626+0.708x,即马铃薯中干物质含量越高,淀粉含量也就越高。     

Changes in carbohydrates and the activity of α-galactosidase,pentosanase and lipase during germination of groundnuts (Arachis hypogea)

The quantitative changes in carbohydrates of two varieties (i.e., red netal and HG-4) of groundnuts during germination have been investigated. On germination, raffinose, stachyose and verbascose decreased gradually up to 48 h and almost disappeared completely in later stages of germination (140 h). Glucose and fructose levels increased 4–6 fold; while sucrose content increased considerably throughout germination in both the varieties of groundnuts. The starch content increased about four fold during germination in both the varieties. The pentosan content was almost constant up to 36 h but decreased in later stages of germination. The oil content decreased significantly from 52 to 8.0%. The fairly high initial α-galactosidase and lipase activity in resting seeds, increased considerably during germination in both the varieties studied. On the other hand the pentosanase activity was not detected up to 36 h of germination but it appears to increase abruptly afterwards.     

Changes in the carbohydrate constituents of chickpea and greengram during germination

A decrease in the concentration of total carbohydrates was observed during 96 hours' germination of chickpea and greengram. However, whilst the starch and oligosaccharide levels decreased, the reducing sugars increased. Starch was the major carbohydrate and about 50% of it was hydrolysed after 96 hours' germination. The amylose proportion of the starches increased during germination. Starches from germinated chickpea and greengram had better swelling power and solubility, but their intrinsic viscosity was lower. Changes occurred in the concentration of hemicelluloses during germination but their composition did not alter. The abovementioned changes, occurring during germination, appear to have a favourable effect on the nutritional value of chickpea and greengram.     

Distribution of Phosphorus and Phytate in Some Nigerian Varieties of Legumes and Some Effects of Processing

Phytate anion, total phosphorus (P), phytate-P, inorganic and residual P contents were determined in different varieties of cowpeas, lima beans and soybeans. The dry seeds were subjected to different processing methods which included cooking, autoclaving, soaking and germination. Germination and soaking were most effective in decreasing phytate contents while cooking and autoclaving only slightly altered total P, phytate and phytate-P contents in all varieties. Germination increased inorganic P contents but effected the highest percentage loss in residual organic P. Soybean contained considerable amounts of phytate anion and despite the reduction through processing, phytate content still exceeded the amount present in all varieties of raw lima beans.     

Changes in differently processed soya bean (Glycine max.) and lima bean (Phaseolus lunatus) with particular reference to their chemical composition and their mineral and some inherent anti-nutritional constituents

The effects of 3 processing techniques: cooking, roasting and autoclaving on the proximate chemical composition, the mineral content and some inherent toxic factors of soya and lima beans were investigated. The processing techniques generally reduced the crude fibre levels and enhanced the extractable fat in the soya and lima beans. The coefficients of variability for crude fibre and ether extract due to the processing techniques of soya and lima beans were 20.9%, 16.0% and 22.3%, 38.1%, respectively. In parallel with decreased ash content in the cooked bean samples, there was a decrease in the K, Mg, Na and P levels relative to the raw bean and also relative to the other processing techniques. Mineral contents of the autoclaved bean samples were generally similar to those of the raw (unprocessed) samples. Under the processing conditions, roasting caused the highest reduction in thioglucoside content (59%) in soya bean while cooking caused the highest reduction in lima bean (78%). Trypsin inhibitor activity (TIA) ranged between 0.59 mg/g sample in the cooked soya bean and 11.6 mg/g sample in the raw bean while the corresponding values for lima bean ranged between 0.59 and 6.3 mg/g sample. Cooking and roasting caused over 90% reduction of TIA, while autoclaving caused 64-69% reduction in both bean samples. Under the assay conditions, haemagglutinating activity was not detected in the cooked and autoclaved soya and lima beans. The need to prevent both functional and nutritional damage to food proteins and other nutrients, resulting from excessive heating, was discussed.     

Structural and some nutritional characteristics of Velvet bean (Mucuna pruriens) and Lima bean (Phaseolus lunatus) starches

Velvet bean (Mucuna pruriens) and lima bean (Phaseolus lunatus) starches were isolated from seeds and their structural characteristics evaluated using XRD, size‐exclusion chromatography and light scattering analyzes. Total starch, available starch, RS and in vitro digestibility were also determined. Structural and nutritional characteristics of Velvet bean and Lima bean starches were compared to those of commercial corn starch. The legumes starches presented a C‐type XRD pattern and crystallite sizes of 43.1 Å for velvet bean and 48.3 Å for lima bean. Lima bean starch average molar mass (4.9 × 10⁶ g/mol) was slightly higher than the velvet bean starch (3.04 × 10⁶ g/mol). Size‐exclusion chromatography indicated structural similarity between the lima bean and corn starches which differed from that of the velvet bean starch. Hydrodynamic radius (R_H) for the velvet bean and lima bean starches was 45.5 and 55 nm, respectively, and their radius of gyration (R_G) was 67.7 and 82.5 nm, respectively. Total starch content in all three starches was greater than 98%. Their complex crystalline structure provided the legume starches lower in vitro digestibility values than the corn starch. RS content in both the velvet bean starch (7.72%) and lima bean starch (5.66%) was higher than in the corn starch, essentially qualifying these polysaccharides as natural dietary fiber sources, with the associated physiologic advantages.     

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     

Nutritional composition of UK retail potatoes,both raw and cooked

Over two seasons, four maincrop potato cultivars together with early varieties, were purchased from a range of retail outlets in three principal consumer areas (London, Birmingham and Glasgow). Samples were analysed for moisture, total nitrogen, non-protein nitrogen, fat, carbohydrates (sugars, starch and dietary fibre), vitamins and minerals. Analyses were carried out on both the raw and cooked (boiled, baked, roast and chipped) tubers every 12 weeks. Values for raw and cooked materials were compared with previously published figures, and cultivar, centre and seasonal effects were identified by analysis of variance. Nutrients found to be lower than the Food Composition Table data were riboflavin and niacin (50%), potassium (40%), iron, copper and zinc (20–30%); thiamin and total folate were 2–3 times higher, total ascorbate, initially similar, declined more rapidly after harvest. These differences were reflected in the values obtained for the cooked potato where the major difference was a reduction in the fat content of chips by about 40%. Cooking losses were similar to those in the Food Composition Tables. The main varietal effects were confined to the vitamins. Centre effects showed that potatoes from Glasgow had less ascorbate and dry matter but slightly more free sugars. The only significant seasonal effect was for total ascorbate where the second season was higher than the first.     

不同玉米品种发芽过程中碳水化合物代谢变化的初步研究

以普通玉米(苏玉24号,SY-24)、糯玉米(紫花糯玉米,ZY)和甜玉米(京晶3号,TY)为试材,研究了不同玉米品种的组分差异及不同发芽阶段生理生化和碳水化合物组成的变化.结果表明:不同品种玉米之间存在组分差异,SY-24的千粒重和直链淀粉含量最高,ZY中未检测到直链淀粉;ZY的水分、还原糖、可溶性糖、Mg、Na和Ca的含量最高;TY中的类胡萝卜素、可溶性蛋白、游离氨基酸、灰分、粗脂肪、Zn和K含量最高.SY-24中未检出Ca;TY和SY-24中Fe含量没有显著差异(P＞0.05),但均显著高于ZY(P＜0.05),分别是ZY中铁含量的4.69和1.04倍.在发芽过程中,芽长、发芽率、呼吸强度逐渐升高,干物质含量逐渐降低;淀粉酶活力而逐渐增加,β-淀粉酶活力显著高于α-淀粉酶活力(P＜0.05);在淀粉酶作用下,淀粉含量逐渐降低,淀粉颗粒逐渐变小,ZY中没有检测到直链淀粉,SY-24和TY直链淀粉含量随发芽时间延长呈先增加后降低,并分别在第24h和第36h达到最大值,分别是未发芽的3.10倍和1.46倍;可溶性糖在发芽过程中呈现波动变化;ZY和SY-24中还原糖含量逐渐增加;TY中还原糖含量呈现先降低后增加的趋势,在发芽地12h达到最低,与未发芽相比降低了15.44％.     

Macronutrients content of Yellow Glacier Lily and Balsamroot; root vegetables used by indigenous peoples of northwestern North America

The macronutrients in two foods used by indigenous peoples of the British Columbia Plateau region were examined. Yellow Glacier Lily and Balsamroot were commonly harvested, processed and stored in large quantities, up until the last three decades, together with many other plant foods. The macronutrients of the two foods, in which the underground bulbs or roots are utilized, are mainly derived from the carbohydrates. Yellow Glacier Lily bulbs have a high starch content, (770 g kg⁻¹ in fresh bulbs, dry basis), and 57 g kg⁻¹ total dietary fibre. They also contain measurable amounts of simple sugars and fructans before and after cooking. Balsamroot, whose taproots were eaten, is another plant indigenous to the region, but unlike Yellow Glacier Lily it contains negligible amounts of starch. The edible portion of Balsamroot has a high total dietary fibre content (250 g kg⁻¹, dry basis), and high fructan content which is reduced to lower molecular weight sugars after pitcooking. The energy derived from the two foods is very similar on a dry basis ranging from 364 to 395 kcal 100 g⁻¹ in the fresh and pitcooked samples.     

Changes in carbohydrates of germinating fenugreek seeds (Trigonella foenum graecum L.)

The effect of germination at 25 °C for 96 h in the dark on the carbohydrates of fenugreek seed was investigated. Reducing, total reducing, non-reducing sugar, and pentosan contents increased. Polysaccharides estimated as starch decreased. Fenugreek contained mucilage (18%), which decreased considerably during germination. The decline in mucilage content was accompanied by a drop in galactan content. Total pectic content did not change, but there was a decline in the high methoxy pectin content, while protopectin, and the low methoxy pectate salts of calcium and magnesium increased. The 70% ethanol soluble carboydrates were chromatographically determined. Fenugreek seeds contained sucrose, raffinose, stachyose, and an unidentified sugar ( I ). A marked increase in sucrose content was observed after germination. Raffinose, stachyose and the unknown sugar ( I ) decreased, while another unknown ( II ) appeared. The two unknown sugars may be members of the raffinose family. Maltose and fructose appeared in measurable amounts after germination.     

Nutritional characteristics,biochemical composition and antioxidant activities of Moroccan Oat varieties

Oat has been recognized as a healthy food for a long time. In this study, physicochemical analysis including, moisture, pH, ash, fibres, proteins, starch, carbohydrates, some minerals, sugars, fatty acids, sterols, total phenolic, and flavonoid contents of four Moroccan Oat varieties (Amlal, Tissir, Zahri and Ghali) were investigated. Additionally, starch morphology has been described according to scanning electron microscopy, and viscosity as measured on a rotary rheometer, increased with stabilization time. Furthermore, Oat extracts were analyzed with regard to their antioxidant activities using DPPH radicals’ cation, Trolox equivalent antioxidant capacity and ferric reducing/antioxidant power. Results from this investigation demonstrated that Moroccan Oat varieties constitute an interesting supplement of natural antioxidants, especially phenolic compounds. Moreover, potassium was the main mineral in Oat seeds (1628.17–2541.52 mg/Kg); also, the oleic, linoleic, and palmitic acids were the dominant fatty acids. While the major sterols were, β-sitosterol, Δ-5-avenasterol and campesterol. Finally, sugar analysis by HPLC-RI indicate that sucrose content was higher than glucose and fructose respectively, and that Ghali and Amlal varieties exhibit an important total sugars levels. Those results highlight the possible contributions of Oat seeds to nutritional therapy.     

糖型与淀粉型木薯后代块根品质与发酵特性

为了研究糖型与淀粉型木薯后代块根品质与发酵特性,测定了28个木薯品系块根的干物质、淀粉、总糖、还原糖、粗蛋白和灰分等主要品质性状。结果表明,淀粉型木薯后代块根的淀粉（14.52%）、总糖（27.48%）、干物质（41.24%）、粗蛋白（1.67%）和灰分（0.25%）含量,总体上比糖型木薯后代块根高;糖型木薯后代块根还原糖含量（2.01%）显著高于淀粉型木薯后代块根（0.61%）（P＜0.05）,而其淀粉含量仅6.62%。相关分析表明,还原糖与淀粉、总糖、干物质和粗蛋白等性状均呈显著负相关（P＜0.05）。通过杂交改良克服负相关,新品系SM03块根的乙醇转化率达到53.7 mL/100 g干质量,产酒精34.73 L/hm2。SM03和SC16只糖化、不经过糊化预处理,酵母发酵分别产酒精31.13 L/hm2、27.80 L/hm2,均是很有推广价值的能源木薯新品种。     

A survey of acrylamide precursors in Irish ware potatoes and acrylamide levels in French fries

Reducing sugars (glucose and fructose) and asparagine levels in three varieties of Irish ware potatoes (Rooster, Record and Oilean) on sale in a local supermarket were monitored over an 11-month period. Samples were processed into French fries using conditions similar to those used for home preparation of fries and acrylamide levels in a selection of samples were measured. A wide range of total reducing sugar levels (fructose+glucose) were observed over the course of the study with values ranging from 152-12,286, 301-8812 and 279-7881 μg/g FW for the Rooster, Record and Oilean varieties, respectively. This resulted in high levels of acrylamide in some samples (up to 2970 μg/kg). In comparison to reducing sugars, asparagine contents were relatively constant for the three varieties and no particular trend in asparagine levels was noted. Both fructose and glucose contents of the tubers were positively correlated with acrylamide content (r=0.809, 0.776, respectively, P<0.001). A negative relationship between Hunter L values and acrylamide content of the French fries was observed (r=−0.712, P<0.001) indicating that L values could serve as a convenient and reliable indicator of acrylamide levels in French fries.     

Carbohydrate constituents of some nigerian maize varieties grown at three soil nitrogen levels

Of eight varieties of maize analysed, average values for constituent carbohydrates in g/100g dry matter were: soluble sugars, 1·61; starch, 62·04; water-soluble polysaccharides, 2·60; alkali-soluble polysaccharides, 6·85 and cellulose, 1·08. Lignin varied from 1·18 to 1·86%. Significant varietal differences (P < 0·05) were found for the carbohydrate fractions, although differences within varieties due to nitrogen fertilisation were not significant. Soluble sugars and starch, which contribute appreciably to the energy value of the maize, ranged between 56·68% for WCUI and 67·12% for Lag ABCD. Predicted digestible energy (DE) and metabolisable energy (ME) values for pigs were in the range 4005–4073 kcal/kg and 3881–3947 kcal/kg, respectively whilst metabolisable energy for poultry varied between 3692 and 4007 kcal/kg.     

Carbohydrate composition of different varieties of cowpea (Vigna unguiculata)

Twenty varieties of cowpea with the following proximate composition: dry matter, 87–94%; crude protein, 24–33% ether extract, 1–2%; crude fibre, 2–5% and ash, 2–5% were analysed for sugar contents, starch, cell wall carbohydrates and lignin. The legume seeds exhibited a total carbohydrate content ranging from 56% to 68%, the major constituent being starch. Starch values as high as 45% to 48% were obtained for some varieties although most values ranged between 37% and 42%. Ethanol-soluble sugars were verbascose, stachyose, sucrose and raffinose in varying amounts but there were only traces of fructose and glucose. Samples had total soluble sugar contents of 6% to 13%. Values for unavailable carbohydrates for most samples were 11% to 13%. Lignin was very low and ranged from 0·6% to 1·8%.     

Effects of germination on the activities of amylases and phenolic enzymes in sorghum varieties grouped according to food end‐use properties

Fifty sorghum varieties were screened to determine the effects of germination on levels of starch, α‐amylase, β‐amylase, phenylalanine ammonia lyase (PAL), peroxidase (POX) and polyphenol oxidase (PPO). Germination decreased starch content, with amylose being more degraded than amylopectin. In germinated grain, α‐amylase activity increased several‐fold in all varieties, whereas β‐amylase activity did not increase uniformly and even decreased in some varieties. Activity of the key enzyme in phenolic biosynthesis, PAL, was detected in only half of the varieties before germination but in all of them after germination. PPO was not activated in germinated sorghum grains, whereas POX activity increased up to tenfold in some varieties. Zymography revealed that germination induced de novo synthesis of several POX isoenzymes, among which an anionic POX isoenzyme (pI 3.1) was ubiquitously present. Amylase and phenolic enzyme activities could be correlated with grain and plant agronomic characteristics. The use of sorghum varieties for local dishes such as ‘tô’, ‘dolo’, couscous and thin porridge could be correlated with amylase and phenolic enzyme activities and the contents of their substrates. The biochemical constituents determined are useful markers for selection of varieties for food utilisation with special emphasis on infant porridges. Copyright © 2006 Society of Chemical Industry