Potato extractives: Sloughing as related to replacement of anions or cations

All anions or cations were removed from potato extract and were replaced by a single, naturally occurring anion or cation in an effort to determine the relative effect of each on the sloughing of potato tissue. The treated extracts were used in cooking soaked potato tissue slices. In the anion series, citrate caused the greatest amount of sloughing. Other cooking media and treatments in decreasing order of effectiveness were untreated extract, malate, oxalate, chloride, and distilled water. In the cation series, sodium and potassium caused significantly more sloughing than the untreated extract. Magnesium and calcium firmed the potato tissue, resulting in less sloughing than that obtained with distilled water.     

Cooking quality of some Dutch potato varieties

Summary The relationships among three methods for evaluating texture (sloughing during cooking, hardness of cooked potato dice and shear press value of French fries) and some chemical constituents (Ca, Mg, K, free pectin, phytin and citrate) were investigated, using the main specific gravity classes of seven Dutch potato varieties. The interplay of these constitutents (except K) in the softening of the texture during cooking was expressed as follows: Only the shear press value showed a relationship with the specific gravity. None of the textural-properties was geverned by the PC PMC number or by water uptake of raw slices. The same properties were determined after 50 and 100 days storage at 10 and 4 C. A decrease in sloughing and hardness, but an increase in shear press value occurred. PCMPC number also increased, but remained quite low, explaining its lack of influence on texture.     

Effect of domestic processing on the cooking time,nutrients, antinutrients andin vitro Protein digestibility of the African yambean (Sphenostylis stenocarpa)

The effects of processing (soaking, dehulling, fermentation and heat treatment) on the cooking time, protien, mineral, tannin, phytate and in vitro protein digestibility (IVPD) of the african yambean (AYB) were examined. The cooking time ranged from 90–155 minutes. Soaking reduced cooking time by about 50 percent. Soaking for 12 hours was the most appropriate to reduce cooking time, tannin and phytate levels. It improved in vitro protein digestibility (IVPD). Prolonged soaking (24 hours) decreased calcium (Ca) and iron (Fe) values by 19 percent and 35 percent, respectively. Dehulling showed that Ca, Fe, magnesium (Mg) and zinc (Zn) were concentrated in the seed coat of the AYB. The seeds soaked and dehulled retained Mg and Zn. Dehulling reduced tannin but had no significant effect on phytate and the IVPD of the AYB except for seeds soaked for 12 hours before dehulling. Soaking for 24 hours before dehulling significantly increased crude protein content by 16 percent (p<0.05). Blanching and roasting increased the IVPD by 8–11 percent. Fermentation had no effect on the crude protein, Ca, Fe, Mg and Zn but significantly reduced phytate content of the AYB. Fermentation had no advantage over heat treatment with respect to improving the in vitro protein digestibility of the AYB.     

Comparison of the cooking behaviour of the potato cultivars Nicola and Irene with respect to pectin breakdown and the transfer of ions

Summary The potato cultivars Nicola and Irene were investigated with respect to cell sloughing, specific cell surface area, release of pectic material and transfer of ions using a model cooking study. Both cell sloughing and the release of pectic material were higher for the mealy-cooking cultivar Irene. As the respective cell size distributions measured were the same for both cultivars, the difference in release of pectic material could not be explained by a difference in the specific cell surface areas between the cultivars. Additionally, it was recorded that during cooking only 20% of the calcium present in non-cooked tissue was transferred into the cooking medium, whereas more than 70% of potassium and citrate were transferred. The ratios D_a.citr2−/D_a.K+ and D_a.Ca2+/D_a.K+ for water and cooked potato tissue revealed that in water, potassium ions diffused faster than citrate and calcium ions. However, in cooked potato tissue both citrate and calcium ions diffused faster than potassium ions.     

Effects of cooking,germination and fermentation on the chemical composition of Nigerian Cowpea (Vigna unguiculata)

The effects of cooking, germination, and fermentation on the chemical composition of cowpea were studied. There were noticeable trends in the protein, carbohydrate and crude fiber as a result of the different treatments. Both the germinated and fermented samples contained more ether extractable lipids than the raw and cooked samples. Untreated raw cowpea contained 5.9 mg/g phytic acid, 1.66 mg/g phytate phosphorus, 3.3 mg/g total phosphorus, 56.8 mg/g total sugar, and no reducing sugar. Cooking the dry beans at 100°C for 1 1/2 hours had little effect on the phytic acid and phytate phosphorus. There were, however, significant decreases in total phosphorus and sugars of the cooked beans. After germination for 24 hours, 48 hours and 72 hours respectively, there was a significant decrease in phytic acid and total sugar and increase in total phosphorus and reducing sugar. Similar results were also obtained when the dry beans was fermented for 24 hours, 48 hours and 72 hours respectively.     

Barley Bulgur: Effect of Processing and Cooking on Chemical Composition

Three barley cultivars (Hordeum vulgareL.) were processed into bulgur by pressure cooking or cooking at atmospheric pressure. The effect of processing on levels of thiamine, riboflavin, minerals (Fe, Cu, Zn, Mn, Ca, Mg) as well as the phytic acid and β-glucan was investigated. Significant decreases (p<0·05) were observed in ash, riboflavin and thiamine contents during bulgur processing. Neither the cooking methods nor the dehulling process had significant influence on the content of Fe, Cu, Zn or Mg. However, the Mn and Ca content of the bulgurs were significantly (p<0·05) lower compared with the corresponding raw barleys. For all cultivars total P and phytate P contents of the bulgurs were significantly (p<0·05) lower compared with the corresponding raw barleys. In contrast, levels of β-glucan were significantly higher in processed bulgur vs raw barley. Protein contents of the samples did not change significantly during bulgur processing. Bulgur processed from barley appeared to retain most of the nutritional value of raw barley, in particular it showed high levels of soluble dietary fibre.     

Irradiation and germination effects on phytate,protein and amino acids of soybean

Influence of irradiation (0.05–0.20 kGy) and germination (24–120 hours) in distilled and tap water on phytate, protein and amino acids of soybean, was studied. Phytate values significantly decreased with increasing germination period and irradiation dose (P<0.01). Irradiation independently decreased the original phytate (212.0 mg/100 g) to a range value of 205.0–190.0 mg/100 g depending upon dose level. Germination of unirradiated seeds for 120 hours in distilled and tap water lowered the phytate to 55.0 and 94.9 mg/100 g (74.1 and 55.2% reduction) respectively. Maximum destruction of phytate to levels of 20.5 and 50.9 mg/100 g (90.3 and 76.0% reduction) occurred during germination of 0.20 kGy samples for 120 hours in distilled and tap water respectively. Total protein content significantly increased during germination (P<0.05) and the increase was more in tap than distilled water. Germination for 120 hours of untreated seeds in tap water increased the essential and decreased non-essential amino acids while in the 0.10 kGy sample, increases in both cases were observed.     

Proximate composition and selected physicochemical properties of the seed,pulp and oil of sour sop (Annona muricata)

Proximate composition and physicochemical analyses were carried out onthe seed, pulp and extracted oil of sour sop (Annona muricata). Theresults showed that the seed contained 8.5% moisture, 2.4% crudeprotein, 13.6% ash, 8.0% crude fiber, 20.5% fat and 47.0%carbohydrate. The seed also contained 0.2% water soluble ash, 0.79%titratable acidity and 17.0 mg calcium/100 g. The pulp was found tocontain 81% moisture, 3.43% titratable acidity and 24.5%non-reducing sugar. Selected physicochemical characteristics includedrefractive indices of 1.335 for the seed and 1.356 for the pulp, specificgravities of 1.250 for the seed and 1.023 for the pulp, pH values of 8.34for the seed and 4.56 for the pulp, and soluble solids contents of1.5 ^°Brix for the seed and 15 ^°Brix for the pulp. Theextracted oil (20.5% yield) had a 60.43% unsaponifiable value,23.54 KOH/g acid value, 100.98 K0H/g saponification value, 1.1 K0H/gperoxide value, 1.464 refractive index, 5.77 pH, 69.5 ^°Brix soslublesolids and 0.2900 specific gravity.     

施肥对天然橡胶胶乳及生胶性能的影响

设置了 5 种不同施肥处理，通过田间试验研究了施肥对天然橡胶胶乳及生胶性能的影响。结果表明：施用 N 肥可以增加胶乳总固形物和干胶含量；施用钾肥或与氮磷肥配施，可降低胶乳中游离钙镁。不施氮肥而只施用磷钾肥会增加生胶灰分含量；氮磷钾肥配合施用可增加生胶中氮含量；磷钾肥配施或氮磷钾（镁）肥配施时，生胶中的挥发物含量较高。施肥可以降低生胶的塑性初值（P0），在一定程度上提高生胶的塑性保持率（PRI），其中施用氮肥后的生胶的塑性保持率显著增高。同时，使用化学肥料可增加橡胶的分子量，其中氮磷钾镁肥配合施用时生胶分子量最大，门尼黏度高。     

The evaluation of experimental potato varieties for use in canning

Three new experimental Wisconsin, high-set varieties of potatoes, (WHS-15, WHS-16, and WHS-17), which in previous studies had yielded a large proportion of small tubers (B-size), were produced in sand and sandy loam locations during three seasons and processed to determine canning quality. Norland, a standard commercial canning variety, was used as control. The experimental varieties were superior or equal to Norland in field performance, producing a high total yield and a large proportion (27–43 percent) of small B size tubers suitable for canning. Product acceptability of the new varieties as estimated by a sensory panel was slightly less than Norland in 1976, but about equal in 1977. Mean specific gravity and total solids of each of the new varieties were somewhat higher than Norland. This was especially evident in the relatively dry 1976 season in which considerable sloughing of processed product was evident. The WHS-17 variety consistently produced the highest yields and tubers of lowest specific gravity.     

Anatomy and compositional variations within potatoes III. Gross compositional gradients

The degree of compositional variations within potato tubers has been related to the development anatomy of the tuber and to exact tissues. The principal component, starch, shows differences in granule size distributions and in composition that appear when the young tuber averages about 1/300 of mature volumetric size. These differences pertain at maturity. When starch differences have been established, growth by cell divisions diminishes and growth by cell enlargement becomes dominant. In the mature tuber the general gradients for specific gravity, percent total solids, and percent total nitrogen decrease from stem end to bud end for cortical, perimedullary and pith tissues. Relationship between specific gravity and total solids is less parallel because differences in cell size and size of minute intercellular spaces also influence tissue density. Relationship between total solids and total nitrogen gradients from cortical tissue to pith were inverse with toal nirogen being higher in those tissues of lower total solids. These variations suggest need for new approaches in basic research on tuber quality improvement.     

Chemical composition of potatoes. VIII. Effect of variety,location, and year of growth on the content of nitrogen compounds

Free amino acid content, total nitrogen, extractable nitrogen, ratio of extractable to total nitrogen, solids content, and specific gravity in Cobbler, Katahdin, Kennebec, Red Pontiac, and Russet Burbank potatoes was studied. Each variety was grown in six different locations (Idaho, Maine, Pennsylvania, Wisconsin, Long Island, and the Red River Valley) during the years 1961 through 1963. The mean values for each factor, with significant differences indicated, are listed along with the high and low range, the coefficient of variation and the overall mean. The percent of total variance contributed by each of the variables and their interactions also are listed. Long Island potatoes had the highest nitrogen and amino acid content. Varietal differences were less significant. Proline was the most variable of the constituents measured. Aspartic and glutamic acids had the highest variability with respect to years grown. The effect of each variable varies from one constituent to another.     

Protein,nonprotein, and total nitrogen in seedlings of potatoes

Analyses for secific gravity, total solids, total nitrogen, protein nitrogen, and nonprotein nitrogen are reported for 73 seedling samples grown in Maine, and for 10 selections grown in Idaho. The interactions between the various constituents, as indicated by regression analysis, are discussed. These samples indicate a potential for breeding a variety of potato with a higher than average protein content, but further work is necessary to determine the inheritance pattern. This work is in progress.     

Phytate Reduction in Whole Grains of Wheat,Rye, Barley and Oats after Hydrothermal Treatment

Whole grains of different cereals have traditionally been prepared with water and heat prior to dehulling, but knowledge of the effect on nutritional properties is limited. The aim of the present study was to investigate if phytate reduction occurred during hydrothermal treatment of whole grains. Wheat, rye, hulled and dehulled barley, hulled oats and naked oats were incubated with either water or acetate buffer (pH 4·8) at 55 °C for 24 h with the exception of oats, which were incubated at 37 °C. Phytate in wheat, rye and barley was reduced by 46–77% when water was used and by 84–99% when acetate buffer was used. The phytate reduction in oats was considerably less, 8–26%, but, after grinding and soaking, phytate was reduced by 72–77% in dehulled oats and by 88–94% in naked oats. Citric acid and citrate buffer was used for pH adjustment in some experiments, and their use resulted in less phytate reduction than when acetate and lactic acid were used. Wet-steeping of naked oats and naked barley in water at 53–57 °C for 20–30 min reduced the bacterial counts by 99·97%, and the addition of acid prevented bacterial growth during the incubations. It was concluded that cereals with reduced phytate content and good hygienic quality can be developed and produced using hydrothermal treatment of whole grains.     

橡胶树种子电导率特性及其与种子活力的关系

用完整的橡胶树种仁在室温下浸泡于无离子水中测定种子渗漏质电导率。研究结果表明,橡胶树种子渗漏质电导率与浸泡时间之间呈直线相关,因品种、种子质量、贮存时间和季节而异,但这种差异是相对稳定的。不同质量的橡胶树种子的电导率之间的显著差异可以在种子浸泡7h内观测到。橡胶树种子电导率与发芽率及籽苗生势之间均呈显著负相关关系。因此,橡胶树种子电导率有可能作为快速测定橡胶树种子活力的一个重要指标。另外,橡胶树种子在敞开贮存期间,种子电导率出现波动性变化现象,这种变化也因品种和种子质量等而异。      

The effect of processing on total organic acids content and mineral availability of simulated cassava-vegetable diets

Changes in pH, titratable acidity and mineral content (Ca, Fe, Mg, Zn) were estimated in processed cassava products while the mineral content of raw and blanched amaranthus vegetable was determined. pH of fresh cassava (6.5) decreased as total organic acid (0.07%) increased with fermentation period. Fufu and lafun had the lowest pH and the highest total organic acids contents. Fermentation of cassava increased the total calcium and iron contents, reduced magnesium level while zinc remained fairly constant in grated cassava but was reduced when soaked in water (for the preparation of fufu and lafun). Fermentation also increased the availability of these selected minerals in both cassva products and simulated cassava-vegetable diets. Blanching reduced the mineral content of amaranthus vegetable but increased mineral availability. Fermentation of cassava and blanching of vegetables play an important role in making minerals more available and these processing methods should be encouraged to potentially ameliorate the disease states associated with mineral deficiency.     

Quick-cooking beans (Phaseolus vulgaris L.): II. Phytates,oligosaccharides, and antienzymes

Effects of the quick-cooking processes on phytate and oligosaccharide levels, and on trypsin and chymotrypsin inhibitors, were investigated in three bean varieties (Phaseolus vulgaris L.: Great Northern, red kidney, and pinto). Beans soaked in distilled water had lower levels of phytate-P than those soaked in a mixed salt solution. Leaching losses of oligosaccharides were nearly the same in different soaking treatments for all the beans except kidney beans. Residual trypsin inhibitor activities (TIA) in cooked quick-cooking beans were about 10% compared with about 20% for chymotrypsin inhibitor activities (CTIA) in the same bean products. -Irradiation was more effective in reducing TIA than CTIA and paralleled destruction by moist heat.Utah Agricultural Experiment Station Journal article no. 2480.     

Nutritive value of prickly pear seeds,Opuntia ficus-indica

Results are reported on the nutritional quality of prickly pear seeds,Opuntia ficus-indica. The seeds contained 16.6% protein, 17.2% fat, 49.6% fiber and 3.0% ash. The meal showed a high amount of iron (9.45 mg %). The contents of Mg, P, K, Zn and Cu were nutritionally significant contributing approximately 10–20% of the Recommended Dietary Allowances (RDA) of these elements per 100 g of dry weight. The amount of Ca represented less than 10% of the RDA for that element. Aspartic acid, glutamic acid, arginine and glycine were the most abundant amino acids making nearly half of the total amino acids content. The seeds were rich in sulfur amino acids (methionine + cystine). Lysine was the first limiting amino acid resulting in a chemical score of 62 for the protein. The in-vitro protein digestibility and the calculated protein efficiency ratio were 77% and 1.82 compared to 90% and 2.50, respectively, for ANRC casein.     

Effects of amino acids and glucose on the fry colour of potato crisps

Summary Amino acids and sugars were removed from slices of potato of the cultivar Record. The slices were then soaked in solutions of the amino acids and various concentrations of glucose to study their effect on the fry colour of crisps. Glutamine was an important amino acid in the development of fry colour intensity at low glucose concentrations and also contributed to the dark fry colour when combined with glucose concentrations above 0.15%. The basic amino acid arginine had a similar but lesser effect and other amino acids used gave the same effect at glucose concentrations above 0.45%. Asparagine could play an important role in the development of fry colour quality and may decrease the grey colour intensity developed by the mixture of amino acids.     

Effect of sprouting on the nitrogenous constituents and mineral composition of pigeon pea (Cajanus cajan) seeds

The study was aimed at evaluating the effect of sprouting on nitrogenous constituents and mineral composition of cream pigeon pea seeds. After 48 and 96h of sprouting, there were increases in % moisture, crude protein, ash except during the 96 h; total nitrogen (TN), total non-protein nitrogen (TNPN); protein nitrogen (PN) and true protein nitrogen (TP). Sprouting caused increases in mineral levels except for phosphorus (P). Sprouting for 48 h offers greater advantage over 96 h.