Diplazium sammatii: Athyraceae (`Nyama Idim'): Age-related nutritional and antinutritional analysis

Tender and mature leaflets and leaves of Diplazium sammatii (`Nyama idim'), were separately investigated for their nutritional and antinutritional properties. Results showed little difference in proximate nutritional contents between tender and mature leaves, except for crude fat, which was present in levels 1.5 times higher in younger than in older leaves. Crude fiber levels were low. Zinc (Zn) and copper (Cu) were higher in younger leaves (6.8 and 3.5 mg/100 g dry matter, respectively, compared to 4.5 and 2.5 mg/100 g dry matter, respectively in older leaves). Older leaves contained higher levels of iron (Fe): 6.7 mg/100 g dry matter, in comparison to 4.3mg/100 g dry matter, in young leaves. Oxalate levels were slightly higher in younger than older leaves. However, the reverse was true for tannin content. Both antinutritional compounds were present in levels which shouldbe safe.     

Nutritional assessment of yam (Dioscorea alata) tubers

The nutrient and antinutrient components of tubers from seven cultivars ofDioscorea alata were determined. The average crude protein content ofD. alata tubers was 7.4%. Starch (75.6–84.3%) was the predominant fraction of the tuber dry matter. Significant differences in crude protein and starch contents were observed among cultivars. Vitamin C content of the yam tubers ranged from 13.0 to 24.7 mg/100 g fresh weight. The results showed yams to be reasonably good sources of minerals. Phytic acid contents of the yams were low, with values ranging from 58.6 to 198.0 mg/100 g dry matter. Total oxalate levels in yam tubers were found to be in the range of 486–781 mg/100 g dry matter, but may not constitute a nutritional concern since 50–75% of the oxalates were in the water-soluble form. The overall results are suggestive of the nutritional superiority of yams compared to other tropical root crops.     

Chemical composition of purslane (Portulaca oleracea)

Purslane (Portulaca oleracea), grown under greenhouse conditions, was harvested at three growth stages and analyzed for total solids, total protein, ash, soluble carbohydrate, and fructose/fructane in whole plants, leaves, stems, and roots. Significant increases were observed in total solids and protein during plant maturation. Leaves had the highest amount of protein in the third growth stage (44.25g/100g dry matter). Roots showed a decline in protein level as the plant aged. Soluble carbohydrate was significantly higher in growth states 1 and 3. Significant variation among growth stages was found with regard to total phosphorous, calcium, potassium, iron, managanese, and copper. Total phosphorus (P) content in leaves was significantly higher than P found in stems and roots. Iron (Fe) content varied significantly among growth stages, and roots and leaves had the highest Fe content (121.47 and 33.21 mg, respectively). Significant accumulation of managanese (Mn) was found in different growth stages. Leaves and roots had significantly higher Mn content than stems.     

香蕉枯萎病高抗品种‘中蕉9号’营养特性的评价

为在巴拿马枯萎病高抗品种‘中蕉9号’推广应用中合理施肥和进行有效的养分管理。以大田正常管理条件下的‘中蕉9号’为试材,采用整株肢解法研究‘中蕉9号’香蕉根、茎、叶、果穗4个器官的干物质氮磷钾养分累积及分配规律,以探讨其养分综合管理技术。结果表明,‘中蕉9号’单株鲜重、干重平均为(145.35±6.42)、(18.18±0.70) kg/株,干物质不足整个植株鲜重的1/8,干物质中灰分仅占8%。4个器官鲜重大小依次是茎（93.53 kg/株）>果穗（33.38 kg/株）>叶（14.93 kg/株）>根（3.51 kg/株）。干物质累积分配规律和鲜重一致,即茎>果穗>叶>根。茎的干重为8.44 kg/株,其中干物质主要分配在假茎中（76%）,球头仅占24%。叶的干重为2.77 kg/株,干物质在叶片中的分配比例是56%,在叶柄中的分配比例是44%。果穗的干重为6.71 kg/株,其中果实的干物质分配比高达94%,果轴的仅占6%。对整株香蕉而言,约2/3的干物质分配到根茎叶中,即2/3的光合产物用于根茎叶的生长,而只有约1/3的光合产物用于果实生长。平均而言,‘中蕉9号’每株累积吸收纯氮116.89 g、纯磷23.67 g、纯钾510.29 g,氮磷钾的吸收比例为1.00:0.20:4.37。氮磷钾吸收累积量在4个器官中的分配大小依次是：茎>果穗>叶>根;根、茎、叶、果穗中的N:P:K比例分别为1.00:0.21:6.82、1.00:0.25:7.38、1.00:0.13:1.96、1.00:0.21:3.10,可见4个器官中,茎部吸收累积氮磷钾总量以及钾的比例最大。‘中蕉9号’根茎叶特别是茎中干物质和钾的吸收累积量远大于巴西蕉是其养分管理值得重视的一个特点。根据‘中蕉9号’生物量和氮磷钾吸收累积分配规律,参考巴西蕉的研究结果,本研究提出‘中蕉9号’的养分管理的建议：孕蕾前应适当控制养分水分供应,限制茎叶徒长和养分消耗;肥料N:P₂O₅:K₂O的比例可参考巴西蕉的营养特性,在孕蕾前采用2.0:0.5~1.0:1.0,在孕蕾至抽蕾期,采用1.0:0.5:2.0,抽蕾后至收获前采用1.0:0.5:2.5~3.0的配方。为了做到更好的养分管理和实现化肥高效利用,‘中蕉9号’茎和叶中积累如此多的碳水化合物和钾以及如何促进他们运输到果实是值得研究的课题。     

Selected nutritional and quality analyses of tomatillos (Physalis ixocarpa)

Proximate composition, total dietary fiber and pH of tomatillos (Physalis ixocarpa) grown in Baja, California were analyzed. Moisture content averaged 92%. On a dry matter basis (DMB), tomatillos contained 11% protein, 18% fat, 13% ash and 5% total dietary fiber. On an as consumed basis (ACB), tomatillos contained 1% protein, 1.5% fat, 1% ash and 0.4% dietary fiber. Carbohydrate (CHO) content was calculated by difference resulting in an average adjusted CHO (excluding dietary fiber) of 53% on a DMB and 4% on an ACB; total CHO (including dietary fiber) was 58 and 4.8%, respectively. Average kcalorie content was calculated to be about 31 kcals/100 g. The average pH of tomatillos was 3.76.     

Nutrient and antinutrient composition of Amaranthus muricatus

The chemical and nutritional composition of theaerial parts of Amaranthus muricatus wasassessed. This is a wild plant growing well in aridand poor soil, which are not suitable for cereals. Thematerial under study was boiled, dried and ground andthen evaluated for chemical, nutritional andantinutritional properties. Protein concentration ofthe amaranth flour was 15.74 g/100 g and total dietaryfiber content was high (53.81 g/100 g), with 79%coming from insoluble dietary fiber. The calciumcontent was 1533 mg/100 g and the Ca/P ratio (5.94)was markedly higher than the value suggested in the1989 Recommended Dietary Allowances. Fifty-ninepercent of the fatty acids present were unsaturatedwith linoleic acid accounting for 40% of the totalfatty acid content. Nitrate, hemagglutinin, trypsininhibitor and saponin contents were within thenon-critical values. Net protein utilization (NPU),true digestibility (tD) and biological value (BV)measurements indicated a nitrogen gain of 74% that ofcasein. The results of this study indicate a nutritivepotential for the A. muricatus leaves, therefore,domestication of this plant is suggested along withassessment of its chemical and nutritionalproperties.     

减少灌水量对强筋小麦花后干物质和氮素积累、转运及产量的影响

为探究灌水量对强筋小麦花后干物质和氮素积累、转运及产量的影响,选用强筋小麦品种中麦998和中麦1062,在防雨棚池栽条件下,春季于拔节期和开花期灌水,每时期设600（W₆₀₀）、300（W₃₀₀）和0 m·hm^-2（W₀）3个灌水量处理,研究了减少灌水量对强筋小麦花后干物质含量、氮素积累和转运、籽粒产量、籽粒蛋白质含量和产量的影响。结果表明,随春季灌水量的减少,强筋小麦植株干物质积累量、氮素积累量、粒重比、叶重比、籽粒产量和蛋白质产量均表现为下降趋势,而蛋白质含量和水分利用效率呈上升趋势。两品种叶片氮素转运量和氮素转运效率以W₃₀₀处理下最高,且叶片氮素转运效率在W₃₀₀和W₆₀₀处理之间均无显著差异。中麦1062在W₀和W₃₀₀处理下水分利用效率无显著差异,中麦998在W₃₀₀和W₆₀₀处理下蛋白质含量无显著差异。综上可见,W₃₀₀处理既能有效提高强筋小麦花后干物质转运量,维持较高的产量和水分利用效率,同时又能提高氮素转运量和籽粒蛋白质含量,达到节水高产的目的。     

Influence of growth conditions on the value of crisphead lettuce

The marketable and nutritional quality of crisphead lettuce as affected by nitrogen supply, cultivar, and plant age at harvest was investigated in six plantings during 1989 and 1990. The optimum yield of marketable heads was obtained at a total nitrogen supply of 150 kg N per ha although only small differences were observed to the yield at 100 and 200 kg total N per ha. The total nitrogen supply included the amount of mineral nitrogen within the rhizosphere. The incidence of dry tipburn in older leaves was clearly decreased by an increased nitrogen supply, especially at late planting. The content of nitrate was increased and the content of dry matter and vitamin C decreased with increased nitrogen supply. The vitamin C content was higher for the cultivar Marius than for Saladin. As plants got older, the nutritional quality of crisphead lettuce decreased because the content of nutrients, especially vitamin C, decreased with increased plant age at harvest.     

Certain functional properties of defatted pumpkin seed flour

Defatted pumpkin (C. pepo andC. maxima) seed flour has potential food uses because of its high protein content, 61.4±2.56%. The functional and electrophoretic properties of the defatted flour were investigated. Polyacrylamide gel electrophoresis and electrofocusing indicated 14 bands of water-soluble protein subunits with isoelectric points between 3.81–8.08 and apparent molecular weights between 19,200 and 97,000 daltons. Minimum nitrogen solubility was observed at pH values between 3.0–7.0 and exceeded 90% at pH above 9.0. Solubility was a function of ionic strength. It appeared that, even at the pH of minimum solubility, the pumpkin seed proteins could be dissolved up to high concentrations by increasing NaCl molarity. The viscosity of flour-water dispersion was affected by flour and salt concentrations, and temperature. The least gelation concentration was 8% (w/v) and the water and oil absorption 24.8±2.03 and 84.4±4.05 g/100 g respectively. Sorption isotherms, BET monolayer moisture and binding energy of sorption were also calculated. Both foam capacity and stability were pH dependent.     

Enzymatic treatment to enhance carotenoid content in dehydrated marigold flower meal

The effect of enzymatic treatments using a commercial enzyme (Econase-cep at pH 5.0 and 0.1% w/w concentration) at different levels of dehydrated marigold meal (5, 10, 15 and 20% dry weight), to enhance carotenoid extraction, was evaluated. The AOAC method consisting of a simultaneous extraction and saponification by using hexane-ethanol-acetonetoluene (10:6:7:7 v/v) and metanolic KOH (40% w/v) was used to evaluate the carotenoid content. The measurement of carotenoids was also carried out in samples in which the water soluble compounds were previously eliminated (AOAC-H₂O). Total carotenoids ranged from 11.4 to 17. 4 g/kg and 18 to 24.7 g/kg of control and treated marigold meal, respectively. Highest amount of carotenoids were noted when 5% level of treated meal was used.     

不同品种桑葚叶总酚含量及其抗氧化活性比较

为了研究不同品种桑葚叶的总酚含量差异及应用价值,以收集引种的40个品种桑葚叶为研究对象,采用超声波辅助提取桑葚叶中酚类物质,以总酚提取率为指标,利用单因素试验和正交试验考察各因素对超声辅助提取桑葚叶总酚提取率的影响;采用DPPH自由基清除能力评价不同品种桑葚叶提取物的抗氧化能力,同时对不同品种桑葚叶中总酚含量及其抗氧化能力进行相关性分析。结果表明：超声辅助提取桑葚叶总酚的最佳工艺条件为：超声温度65 ℃、超声时间30 min、固液比1∶45（g/mL）、乙醇浓度60%,4个因素对桑葚叶总酚提取率影响大小顺序为：超声温度>超声时间>固液比>乙醇浓度。不同品种桑葚叶总酚含量差异较大,其中‘条桑五号’总酚含量最高,为（26.35 ± 0.29）mg/g,‘滇桑’总酚含量最低,为（20.44 ± 0.15）mg/g;不同品种桑葚叶抗氧化活性也存在差异,且趋势与总酚含量基本一致,‘条桑五号’桑葚叶抗氧化活性最强,清除DPPH自由基能力IC₅₀为（77.64 ± 0.34）mg/L,总抗氧化能力（FRAP）TEAC值为（2.58 ± 0.11）mmol/g;‘滇桑’桑葚叶抗氧化活性最弱,清除DPPH自由基能力IC₅₀为（210.30 ± 0.19）mg/L,总抗氧化能力（FRAP）TEAC值为（0.73 ± 0.04）mmol/g。桑葚叶总酚含量与其提取物抗氧化能力呈正相关,选择总酚含量高的桑葚品种栽培,可提高桑葚的综合附加值。     

施氮对玉米产量和氮素积累及相关生理指标的影响

通过田间试验研究施氮对玉米产量、氮素积累及相关生理指标的影响。结果表明,施氮使玉米产量提高,与对照处理差异达极显著水平(P<0.01)。施氮处理使玉米植株的氮素积累量、叶片叶绿素含量、SPAD值、植株中硝态氮和可溶性蛋白含量均增加。相关分析表明,玉米植株干物质积累量与氮素积累量呈极显著正相关;植株干物质积累量、氮素积累量均与植株中硝态氮含量呈极显著正相关。因此,可用植株中硝态氮含量作为预测植株吸氮量及生物量的参考,为指导农业生产中合理施用氮肥提供依据。     

Nutrient and antinutrient profiles of raw and fermented cocoa beans

Freshly harvested cocoa bean was subjected to natural fermentation for 3, 6, 9 or 12 days. The proximate, mineral, hydrocyanate (HCN), oxalate and theobromine levels in the products were determined and compared with those of raw (unfermented) cocoa. The latter sample had the following composition: protein (N×6.25), 17.5; lipid, 62.9; ash, 4.4; fibre, 5.9; and nitrogen-free extract (NFE), 9.3% dry matter. The effect of fermentation was variable, depending on duration and the nutrient under consideration. At day 3, protein content (17.6) was not different, but at day 6 (19.8) was higher (p<0.01), while days 9 and 12 (14.6 and 15.2, respectively) were lower (p<0.01) in comparison with the raw value. Inorganic P steadily decreased from 201.0 (raw) to 102.0 mg/100 g dry matter (day 12) but only the days 9 and 12 values were significantly different (p<0.05), whereas Ca increased from 29.2 (raw) up to 60.4 mg/100 g dry matter (day 3). The antinutrients, HCN, oxalate, and theobromine decreased with increasing duration of fermentation. The decreases for days 6, 9 and 12 were significant (p<0.05). The results are discussed with regard to optimization of the duration of cocoa fermentation for improved nutrient profile.     

Effect of some variables on the extractability of proteins,urease activity,free alpha-amino groups and soluble carbohydrates from soybean meals

The effect of several variables on the extraction of soybean meal protein has been investigated. Solubility studies of the meal show that globulin is the main protein component. Overnight suspension and a meal to solvent ratio 1:10 (w/v) were found to extract maximum amount of protein in distilled water adjusted to pH 6.4 (91.07%). More protein was extracted by diluted sodium hydroxide solutions (0.02 M) adjusted to various alkaline pH-values. Results with several other salts show that concentration as well as pH are very important factors in controlling the percentage of protein extracted. The optimum temperature of extraction was 70°C for 30 minutes, although over a temperature range of 60–75°C the extraction remains essentially constant. Destruction of urease activity was achieved by heating the suspended meal at 75°C for 45 Min. The kinetic inactivation of the enzyme was studied and the energy of inactivation was found to be 32.575 K cal. The level of free alpha amino groups in soybean meals ranged from 5.50 grams: 16 gram nitrogen in meal extracted with 0.1 N HCL adjusted to pH 5.0 to 1.71/100 grams protein (in meal extracted with distilled water.). Their level correlated significantly (p=0.01) upon heat treatment with the carbohydrate content of the corresponding meal. Contrary tothe protein solubility pattern, the -NH₂ groups decrease considerably upon longer exposure to temperatures between 60–75°C.     

Selected nutritional components and sensory attributes of cowpea (Vigna unguiculata [L.] Walp) leaves

Reports on the nutritional composition of cowpea leaves have been limited to a small number of lines and the palatability characteristics of leaves apparently have not been studied. This study was therefore undertaken on cowpea leaves to determine the nutrient composition of fifteen varieties and the sensory attributes of ten varieties grown in Ghana. Nutritional components studied were moisture, protein, phosphorus and ascorbic acid. The sensory attributes included leaf size, taste and overall acceptability. There were significant (p > 0.05) differences among varieties in all nutrient components (fresh and dry weight basis), leaf size and overall acceptability. The nutrient composition values, on a dry weight basis, ranged from 9.4 to 13.0% for moisture, 303.8 to 468.9 mg/100 g for phosphorus, 33.5 to 148.0 mg/100 g for ascorbic acid, and 27.1 to 34.7% for protein. Differences in the sensory scores of leaves for taste were not significant (p < 0.05). Overall acceptability positively correlated with leaf size. Moisture content was negatively correlated with overall acceptability, phosphorus and ascorbic acid. Results can be exploited in a breeding program to develop nutritionally superior and acceptable cowpea varieties which can be used for harvesting of both leaves and seeds.     

Nutrient content of young cassava leaves and assessment of their acceptance as a green vegetable in Nigeria

Cassava (Manihot esculenta Crantz) leaves contained a high level of crude protein (29.3–32.4% dry weight) compared to a conventional vegetable,Amaranthus (19.6%). Ash was 4.6–6.4% in cassava leaf samples but 13.1% dry weight inAmaranthus. Dietary fibre was very high in all samples (26.9–39% dry weight) while HCN-potential was low (5.1–12.6 mg/100 g dry weight). Tannin was the highest in IITA red cassava leaves (29.7 mg/g) and the lowest inAmaranthus vegetable. In vitro digestibility was very low in oven dried samples (15.6–22.7%). Blanching increased protein content (exceptAmaranthus) and in vitro protein digestibility but decreased ash, minerals, dietary fibre and tannin, while HCN-potential was unchanged. Grinding reduced both HCN-potential and tannin by 84 and 71% respectively while oven drying only reduced the HCN content marginally. Preference studies showed that the highest percentage of respondents (25.3%) preferredAmaranthus vegetable, followed by Celosia (17.5%), Talinum (12.4%), garden egg (11.5%), with cassava leaves as the least (0.5%). Organoleptic evaluation rated cassava leaf soup inferior toAmaranthus in terms of appearance, colour and texture but equal in terms of taste and flavour and overall acceptability.     

Protein improvement in Gari by the use of pure cultures of microorganisms involved in the natural fermentation process

The ability of microorganisms involved in cassava mash fermentation to produce and improve protein value by these microorganisms during fermentation was studied. Standard microbiological procedures were used to isolate, identify and determine the numbers of the organisms. Alcaligenes faecalis, Lactobacillus plantarum, Bacillus subtilis, Leuconostoc cremoris, Aspergillus niger, A. tamari, Geotrichum candidum and Penicillium expansum were isolated and identified from cassava waste water while standard analytical methods were used to determine the ability of the isolates to produce linamarase and the proximate composition, pH and titrable acidity of the fermenting mash. The linamarase activity of the isolates ranged from 0.0416 to 0.2618 micromol mL(-1) nmol(-1). Bacillus subtilis, A. niger, A. tamari and P. expansum did not express any activity for the enzyme. Protein content of mash fermented with mixed fungal culture had the highest protein value (15.4 mg/g/dry matter) while the raw cassava had the least value (2.37 mg/g/dry matter). The naturally fermented sample had the least value for the fermented samples (3.2 mg/g/dry matter). Carbohydrate and fat contents of naturally fermented sample were higher than values obtained from the other fermented samples. Microbial numbers of the sample fermented with mixed bacterial culture was highest and got to their peak at 48 h (57 x 10(8) cfu g(-1)). pH decreased with increase in fermentation time with the mash fermented by the mixed culture of fungi having the lowest pH of 4.05 at the end of fermentation. Titrable acidity increased with increase in fermentation time with the highest value of 1.32% at 96 h of fermentation produced by the mixed culture of fungi. Thus fermentation with the pure cultures significantly increased the protein content of mash.     

马铃薯块茎中干物质与蛋白质、维生素C及还原糖的关系

本试验对40份材料块茎中的干物质、粗蛋白、维生素C以及还原糖进行了分析,其中包括普通栽培种(Solanum tuberosum)20份,新型栽培种(Neo-tuberosum)5份,普通栽培种×新型栽培种杂种5份,二倍体栽培种(S.Phureja)9份,二倍体杂种(Neo-tuberosum双单倍体×S.phureja)1份。结果表明,干物质(％)、干物质中粗蛋白(％)、鲜薯中粗蛋白(％)、V_c(mg/100g鲜薯,以及还原糖含量(％)的平均数和标准差分别为19.8893±2.2448,11.9805±2.0367,2.3640±0.3881,8.5288±2.04322和0.6113±0.3031;干物质和干物质中的粗蛋白含量呈极显著负相关(r=-0.4118~(**)),但和鲜薯中粗蛋白含量呈不显著正相关(r=0.2083);干物质和V_c含量呈极显著正相关(r=0.4246~(**)),和还原糖含量呈不显著负相关(r=-0.2769)。     

An evaluation of the effect of Bacillus cells and Bacillus spores in association with cowpea granules as starter cultures for the fermentation of African oil bean (Pentaclethra macrophylla Bentham) to `ugba'

Studies on the improvement of the traditional production of `ugba',a protein-rich fermented African oil bean seed product, were undertaken,by developing starter cultures of Bacillus subtilis cells andspores in association with cowpea granules. The viability of the cellsin association remained stable at 94.5% for 6 months at 30 <sup>°</sup>C and for up to 10 months at 4 <sup>°</sup>C while the viability of the sporesin association remained stable at ca. 96% for up to 10 months at both4 and 30 <sup>°</sup>C. The starter cultures resulted in high increases inprotease activity from ca 2.8 mg N/min to about 51.6 ± 0.4 mg N/minin 48 h and a corresponding increase in amino-nitrogen content of ca2.0 ± 0.2 mg N 100 g dry matter (DM) to ca 18.5 ± 0.3 mg N/100g (DM) during the same period. Changes in the protease activity of thenatural process were gradual and increased from 3.0 mg N/min to 38.0 ±0.8 mg N/min after 5 days of fermentation. The maximum amino nitrogencontent of `ugba' produced by the starter cultures (18.5 ± 0.3 mgN/100 g DM) after 2 days was significantly (p < 0.05) higher than themaximum amino nitrogen content (12.5 ± 0.8 mg N/100 g DM), of `ugba'obtained by the natural process. `Ugba' produced by the starter cultureswere well accepted and compared favorably with the natural product.     

Studies on the influence of temperature,relative humidity and microenvironment on the natural fermentation of African oil bean seeds to ‘Ugba’

Studies on the enhancement of the traditional production of Ugba (a protein-rich fermented food) from African oil bean seeds were undertaken by fermenting the bean seeds at different temperatures, relative humidities (RH) and microenvironments. Fermentation was monitored by pH, texture, amino-nitrogen content and the viable cell count of the substrate. The 40 °C, 98% RH or the 130 m high density polyethylene (HDPE) treatment increased the fermentation microflora from ca. 106 CFU/g to ca. 108 CFU/g with high initial changes in pH (5.8–ca. 7.9) and texture (2.0 kg/cm2 to between 1.4 kg/cm2 and 0.9 kg/cm2) in 24 hours. Products with amino-nitrogen contents of between 12.00 mg N/100 g dry matter and 14.00 mg N/100 g dry matter were obtained in 3 days. The cell count of the 30 °C, 80% RH or 70 m treatment increased from 106 CFU/g to ca. 107 CFU/g and the pH increased from 5.8 to about 6.7 with a coincident decrease in the texture value from 2.0 kg/cm2 to about 1.7 kg/cm2 in 24 hours. Products with amino-nitrogen contents between 15.00 mg N/100 g dry matter and 19.2 mg N/100 g dry matter were obtained after 3 days. Changes in the fermentation indicators were not significant at p0.05 (pH and texture) and at p0.01 (amino-nitrogen) after 3 days for the 25 °C, 59.9% RH or 50 m low density polyethylene (LDPE) treatment. Products of fermentation at the combined optimal conditions (80% RH, 35 °C and 70 m HDPE) compared very well with the traditionally fermented products in terms of pH, texture and amino-nitrogen content.