Study on the protein fractions extracted from the muscle tissue of Pinctada martensii and their hydrolysis by pancreatin

Pinctada martensii muscle proteins were separated into water‐soluble, salt‐soluble and insoluble protein fractions. The salt‐soluble protein fraction was the most abundant, comprising approximately 66.3% of the protein, followed by the water‐soluble and insoluble protein fractions in decreasing order. sodium dodecyl sulphate polyacrylamide gel electrophoresis profiles showed that 35‐ and 97‐kDa peptides represented the highest proportions of the water‐soluble and salt‐soluble protein fractions, respectively. The three protein fractions contained high levels of flavourful amino acids (Glu, Asp, Ala and Lys), with the water‐soluble protein fraction having the highest level (47.1%). The size exclusion chromatography profiles of the water‐soluble and salt‐soluble protein pancreatin hydrolysate demonstrated no significant differences in the molecular weight distributions in the >20 000, 5000–10 000 and 2000–5000 Da fractions, while those of the insoluble protein pancreatin hydrolysate were different. In conclusion, the results provided some basic information that would contribute to the utilisation of these protein fractions.     

Influence of solvent extraction on the dietary fibre fractions of alfalfa protein concentrates

“Freezing curd” was prepared from alfalfa juice and extracted with 2-propanol, either untreated or after washing with water. The soluble and insoluble dietary fibre fractions of the two extracted concentrates and the unextracted freezing concentrate were analysed to assess the effect of extraction on fibre content. Compared with unextracted “freezing curd”, direct extraction with 2-propanol without washing increased the insoluble and soluble dietary fibre fractions by approximately 55% and 52% respectively, while washing with water followed by extraction with organic solvent led to an increase of about 79% and 28%, respectively. Thus, the washing with water lowered the soluble fibre by around 16%. Analysis of the ash and proteins in the crude fibre residues showed that while the ash content was similar in the residues for both the soluble and insoluble fibre, the protein content was much higher in the insoluble fibre residue.     

The effect of metal ion content on the viscosity of gum ghatti

Cold water extraction of gum ghatti gives a soluble gum and an insoluble gel. The two fractions were shown by potentiometric titration to have the same acid equivalent weight and to be largely in the salt form, with less than 10% in the free acid form. Quantitative analysis of the two fractions for metal ion content showed that the gel fraction was largely a calcium salt. The soluble fraction contains calcium, potassium, sodium, and magnesium. Precipitation of the calcium ions reduces the viscosity but the original viscosity is not restored by addition of calcium ions.     

Biochemical effects of unsaponifiable lipidic components of avocado and soya bean administered percutaneously on the connective tissue components of hairless rat skin

The unsaponifiable lipidic fractions of avocado and soya bean were administered percutaneously, on the dorsal skin of hairless rats for 15 days, in a 5% sweet almond oil solution. This treatment produced a modification of dermal connective tissue components. The biochemical analysis showed an increase of soluble proteins, especially of salt soluble collagen together with a decrease of proteins insoluble in neutral buffer. The ratio, soluble proteins:insoluble proteins, increases as well as the ratio soluble collagen: insoluble collagen. These modifications can be considered as a result of the activation of connective tissue metabolism. The above results are in agreement with those obtained when the unsaponifiables were administered per os to rats. Effets biochimiques, sur le tissu conjonctif sous cutané des insaponifiables de soja et d'avocat adminstrés par voie percutanée chez le rat sans poils     

Differences in the mineral composition of sound and disordered apple fruits and of sound and pitted tissue

Separation and analyses of sound Cox's Orange Pippin apples and those with disorders, after storage for 18 weeks at 3.3°C, revealed that sound apples had the lowest, apples rotted by Gloeosporium spp slightly higher, apples with bitter pit higher, and apples affected by breakdown even higher proportions of calcium in the residue after extraction with distilled water, although total concentrations of calcium in these samples were in the reverse order. Lower proportions of calcium, magnesium and potassium were extracted by 75% ethanol from fruit with breakdown than from sound apples, and similarly lower proportions of magnesium, and magnesium and potassium were extracted by water from apples with bitter pit and breakdown, respectively. Proportions of phosphorus extracted by either solvent were not obviously related to disorders. The high concentration of magnesium in pitted tissue, in relation to that in adjacent sound tissue, was evenly divided between the fractions soluble and insoluble in water, but that of calcium was mainly in the insoluble fraction.     

Antioxidant activity and dietary fibre in durum wheat bran by-products

Milling of wheat generates by-products, which can be used to improve the technological performance and/or to integrate foods with healthy compounds. The aim of this paper was to select fractions of durum wheat bran having different functional and nutritional characteristics. Wheat bran by-products were obtained by an industrial milling process. Beside the single fractions, two commercial products Bran & Brain 50 and 70, obtained by blending some of the durum wheat fractions were also studied. All samples were investigated for water holding capacity, soluble and insoluble dietary fibre content and for their antioxidant activity. The soluble fibre content of the durum wheat by-product ranged between 0.9% and 4.1%; while that of insoluble fibre between 21% and 64%. B&B 70 has a TDF content of 61%, while B&B 50 has 42%. The water holding capacity of each fraction is strictly related to the amount of insoluble fibre and to the granulometry of the by-products. Cooking-extrusion process does not affect the amount of soluble fibre; by contrast, a significant increase of the insoluble fibre was detected. The antioxidant activity is higher for the internal bran fraction and it increases in fractions having reduced granulometry. The antioxidant activity of some durum wheat by-product fractions is comparable to that of widespread fruits and fresh vegetables, likely due to the presence of fibre-bound phenol compounds. The high fibre content and antioxidant activity of durum wheat bran by-products can be of particular interest for their use in cereal-based products.     

小麦麸皮及面粉戊聚糖对面团特性及面包烘焙品质影响的比较研究

从小麦麸皮和面粉中分别制备水溶和水不溶戊聚糖，将其以0．5％的比例添加到面粉中，以研究其对面团特性及面包烘焙品质的影响。研究发现，小麦麸皮水溶戊聚糖对面团特性及面包烘焙品质的影响与面粉中的水溶戊聚糖相似，可明显改善面团特性及面包烘焙品质，主要体现在：可增加面团的粉质吸水量，增加面团的稳定时间，增加面包的体积，改善面包的内部质构；小麦麸皮水不溶戊聚糖对面团特性及面包烘焙品质有明显的弱化作用；而面粉中的水不溶戊聚糖则对面团特性及面包烘焙品质影响不大。     

HYDROGEN SULFIDE PRODUCTION BY HEATING DIFFERENT PROTEIN FRACTIONS OF TUNA MEAT

Raw albacore tuna was separated into water-soluble and water-insoluble fractions. The water-soluble fraction was separated into two fractions by trichloroacetic acid (2.5%). The water-insoluble fraction was extracted with NaCl (0.45 M), and then the insoluble fraction was further extracted with urea solution (6 M). H₂S production upon heating of each fraction was determined by the reflux-trap technique. Water-soluble proteins produced 71% of the H₂S, while the corresponding contribution from the insoluble fraction was 29%. Non-protein soluble components and salt-soluble proteins produced insignificant amounts of H₂S. Significant increase in the amount of H₂S was observed when water-insoluble proteins were treated with urea and TCA solutions.     

Polysaccharides of Winged Beans (Psophocarpus tetragonolobus [L.] DC), Variety TPT-2

Variety TPT-2 contains little or no starch. Hot water extraction of defatted and partially deproteinized flour yielded soluble and insoluble polysaccharide fractions in yields of 11 and 28%, respectively. Fractional precipitation of the soluble polysaccharides yielded a predominant Fraction I and a minor Fraction II. Fraction I contained 96% polysaccharide. Fraction II and the insoluble fraction contained 81 and 72% polysaccharide, respectively, the remainder being protein, ash and lignin. Fraction I polysaccharide is predominantly (76%) galactan, but it also contains 18% uranic acid. The Fraction II polysaccharide appears to be predominantly arabinogalactan, but contains 15% uranic acid. Cellulose (41%), galactan (25%), xylan (14%) and acidic polysaccharides (15%) predominate in the insoluble polysaccharides.     

SURFACE PROTEIN OF BROILER MEAT CHUNKS AS OBTAINED BY WASHING

Surface proteins, both soluble and insoluble, extracted from chicken breast and thigh meat chunks with water or 3% NaCl solution were studied. Soluble proteins were separated by an ammonium sulfate gradient precipitation method, quantified, and characterized using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The quantities of both soluble and insoluble proteins from chicken breast meat chunk surfaces were higher than those of the thigh meat. The 3% NaCl solution extracted more soluble proteins, particularly those of molecular weight greater than 66,000 daltons, than that extracted by plain water. Most of these higher molecular weight proteins were satisfactorily precipitated by the addition of 20% ammonium sulfate. The amount of extracted water and salt soluble proteins from blended meat chunks were 3.00 and 4.75 times higher than those from washed suspensions, respectively. An increase in mixing time also enhanced the exudation of proteins to the meat surfaces.     

Removal of Phytate from Great Northern Beans (Phaseolus vulgaris L.) and Its Combined Density Fraction

The effect of pH on the dissociation of phytate complexes and subsequent removal of phytate from Great Northern bean (GNB) flour and its combined density fraction (CDF) was investigated. The largest amount of phytate removed was from GNB flour and CDF dispersions adjusted to pH 7.0 during dialysis. Dialyzed, unadjusted GNB flour and CDF respectively contained 55.4% and 59% of phytate in water-soluble form. The results indicate that phytic acid is present in GNB as a water soluble salt with a M.W. less than 1,000 daltons, water soluble complex with M.W. more than 1,000 daltons, and water insoluble complex. The presence of phytate in the CDF did not affect in vitro digestibility of CDF proteins.     

Mineral composition of isolated fibre fractions from artichoke and the effect of phosphate buffer on its structure and mineral content

Soluble and insoluble dietary fibre of artichoke heart were extracted in water and phosphate buffer to determine their mineral contents and to evaluate the effect of the extraction medium on fibre structure (studied by scanning electron microscopy) and mineral composition (determined by X-ray microanalysis and atomic absorption spectrophotometry). The undialysed soluble dietary fibre extracted with phosphate buffer showed a different structural organisation from that extracted with water. X-Ray microanalysis of both soluble fractions showed some differences between the Na, K, Ca and P contents, and also between the Na contents of the insoluble fractions. However, when the samples were dialysed, differences in morphology and structure between the soluble fractions were not observed. A study of the mineral composition by atomic absorption showed differences between both soluble fractions and both insoluble fractions as regards Na, Ca, Mg and Fe.     

Fractionation of water insoluble solids and extraction of pectins from residues of juice-extracted satsuma mandarin fruit by wet grinding

The waste biomass residue from satsuma mandarin juice production was extracted by wet-fine grinding and separated by centrifugation into insoluble and soluble fractions. The insoluble material was wet-screened into four fractions and analysed for crude fibre and total hydrolysable sugars. Crude fibre was almost exclusively in fractions containing particles over 50 μm, comprising about 65% of the insoluble material; this could provide a raw material high in crude fibre. The remaining insoluble fraction was almost devoid of crude fibre.
The soluble extract contained up to 63% of the total pectic substances with very similar methoxyl contents and degree of esterification, but double the viscometric molecular weight of a standard citrus pectin. The method provides an alternative to that of hot acid extraction.     

Untersuchungen an Polysaccharid-, Pektin- und Ballaststoff-Fraktionen von Sanddornbeeren

The alcohol-insoluble substance (AIS) was prepared from freshly picked buckthornton berries (Hippophae rhamnoides L.) (4.70% of the fresh substance). By sequential extraction with water, ammonium oxalate, 0.05 N HC1 and 0.05 N NaOH, the following quantities of galacturonan/ 100 g AIS were obtained: 0.15 g, 0.4 g (ca.), 0.94 g, 2.29 g resp. These pectin extracts were purified as Cu²⁺ salts. After dialysis they were fractionated into a water-soluble and a water-insoluble part. In these fractions Glc, Gal and Xyl were the predominant neutral saccharide units. Ara, Rha and Man were present in smaller amounts. A higher GalA content (in g per 100 original AIS) was found in the soluble fractions (with the exception of the alkali extract). The pectins from buckthornton berries are middle-esterified and partially acetylated. The composition of the AIS was determined as 9.25% pectin, 34.8% protein and 38.9% total polysaccharides. In the residue after sequential pectin extraction (RE), which contained 60.0% of the AIS, 3.89% pectin, 12.9% protein and 28.0% total polysaccharides were found. By the enzymatic method the percentages of soluble and insoluble dietary fiber were estimated as 13.6 % and 34.1% respectively, whereas the RE contained 5.1% soluble and 34.4% insoluble fiber. The following dietary fiber fractions were determined by the detergent method for both preparations: in case of AIS 36.2% NDF, 3.0% NDF filtrate, 28.0% ADF and 9.6% lignin were found to be present, whilst in the RE, the following components were estimated: 32.8% NDF, 1.4% NDF filtrate, 26.1% ADF and 10.1% lignin. The data presented relates to 100 g original AIS. The water binding capacity was observed to decrease from 7.50 g H₂O (AIS) to 4.26 g H₂O (RE) per 1 g original AIS. For both of these preparations, more than 40 % of bound water was found in the NDF fractions and approximately 30% in the ADF fractions.

     

Some nitrosoamino acids in bacon adipose tissue and their contribution to the total N-nitroso compound concentration

The levels of nitrosoamino acids and apparent total N-nitroso compounds in the adipose tissue of raw bacon have been examined. Nitrosoamino acids were detected in 80% of the samples in levels of up to 0.2 mg/kg. Apparent total N-nitroso compounds were present in all samples in concentrations of between 0.4 and 3.7 mg (N-NO)/kg. Nitrosoamino acids accounted for approximately only 1% of the apparent total N-nitroso compounds. The majority of the apparent total N-nitroso compounds in the adipose tissue were associated with the insoluble connective tissue fraction, with the remainder present as chloroform soluble species.     

The distribution of nutrient elements in cell wall and other fractions of the herbage of some grasses and legumes

The distribution of 10 nutrient elements was assessed in three fractions of herbage samples of perennial ryegrass, tall fescue, white clover and lucerne. The cell wall fraction, prepared by mechanical disintegration of undried material, contained the following proportions of the total herbage content of the major elements: N, 2.9–16.4%; P, 3.0–6.9%; S, 3.6–17.2%; Ca, 11.3–51.8%; Mg. 6.4–27.6% and K, 0.1–1.7%. Substantial though more variable proportions of the trace element cations, Fe, Mn, Zn and Cu were also present in the cell wall fraction. The extent to which the elements were soluble in water was assessed by analysis of the water-insoluble fraction prepared from freeze-dried samples of each herbage. The proportions of the total herbage content of the major elements soluble in water were: N, 30–57%; P, 80–92%; S, 35–71%; Ca, 48–69%; Mg. 65–83% and K, 90–96%. With the trace element cations the proportions soluble in water were more variable, though they were generally less than 70% of the total. The extent to which the various elements were soluble in 80% aqueous ethanol was assessed by analysis of the insoluble fraction prepared from freeze-dried materials. With each of the major elements, smaller proportions of the total herbage content were soluble in 80% ethanol than in water, which may reflect in part the lower solubility of proteins and pectin. With the trace element cations, the differences in solubility between 80% ethanol and water were generally small and inconsistent.     

Effect of hydrothermal processing on carrot carotenoids changes and interactions with dietary fiber

The aim of the studies was to determine the effect of different methods of heat treatment on carotenoids changes and their interactions with insoluble and soluble dietary fiber. Three industrial varieties of carrot--Simba, Caropak and Fayette constituted the experimental material. Carrot cubes were subjected to heat treatment by putting in water with or without citric acid, or in a convection-type steam furnace. The total content of alpha- and beta-carotene was determined in all kinds of pureed carrots. Its amount bounded with insoluble dietary fiber and pectins was also determined. Changes in soluble and insoluble fractions of dietary fiber during hydrothermal treatment were also determined. It was found that the content of trans alpha- and beta-carotene in carrots decreased significantly (p < 0.05) after heat treatment, compared with the control sample. The loss observed during heat treatment in water was higher (up to 50%) than in the case of a convection-type steam furnace. The highest decrease in the content of insoluble fraction of dietary fiber and the highest increase in soluble fraction were observed after treatment with the use of steam. An analysis of interactions between carotenoids and dietary fiber fractions after hydrothermal processing shows their stronger affinity to forming bonds with pectins than with insoluble fiber. It was also found that the effect of heat treatment parameters was significant--the highest (by six times) increase in the content of beta-carotene bounded with pectins was noted in pureed carrots processed in a convection-type steam furnace.     

In vitro fermentation of sugars, grains, and by-product feeds in relation to initiation of ruminal lactate production

In vitro fermentations of various sugars, grains, and by-products were conducted to investigate the relationships between soluble carbohydrates and initiation of ruminal lactate production. Fermentation of hexose sugars, both monosaccharides and disaccharides, resulted in greater accumulation of lactate than did fermentation of pentoses. Results of fermentation of grains and by-products, in order of greatest to least potential to produce lactic acid, were steam-flaked barley = barley = wheat greater than moisture corn = sorghum grain. Water-soluble fractions of the grains and by-products were more rapidly fermented to lactate than the insoluble fractions. Combining 10% soluble fractions from wheat, barley, and steam-flaked barley with 90% insoluble fractions from corn resulted in significant increases in lactate concentration. Analysis of sugar composition of these water soluble materials indicated that monosaccharides and disaccharides constitute 23 to 46% by weight. Data suggest that water-soluble materials play a role in initiation of lactate production from grains, and further production is dependent on starch fermentability.     

MEAT EMULSION STABILITY. Influence of Hydrophilic Lipophilic Balance, Salt Concentration and Blending with Surfactants

SUMMARY –The 'required' hydrophilic-lipophilic balance (HLB) of various animal fats used in sausage making was determined and found to be approximately 14. The HLB of post- and prerigor mutton semitendinosus muscle, measured in 3% NaCl solution, was 13 and 14.6 respectively. The HLB's of mutton protein fractions and nonmeat proteins used in sausage making were determined. The proteins soluble in 3% saline had a higher HLB than insoluble proteins. The optimum salt concentration for mutton emulsion stability was 4%. Blending of meat and nonmeat proteins improved the meat emulsion stability, best results being obtained with a ratio of mutton to skim milk powder, 100 to 15 (w/w). Blending meat and nonionic surfactants improved the emulsion stability only when surfactants having an HLB of 15 were used.     

Preparation and analysis of dietary fibre constituents in whole grain from hulled and hull-less barley

Sixteen different barley samples (7 of which were hull-less; H-L) were milled and subjected to pre-extraction with ethanol and hexane. Water soluble materials (WSM-TP-AI), containing mostly β-glucans, were purified from the hot water extracts by the use of heat-stable amylase. Crude arabinoxylans were extracted by an alkali solution (WUM-B-S) and purified by the use of β-glucanase and amyloglucosidase, giving AX. Finally insoluble fibre residues were obtained (WUM-B-R). GC and NMR analyses revealed no marked quantitative and qualitative differences of β-glucans or the water-soluble arabinoxylans in WSM-TP-AI between the H-L and the hulled (H) varieties. Significant differences among the two barley types were found in the Ara/Xyl ratio of the starting materials as well as the alkali soluble material (WUM-B-S) and the alkali insoluble residue (WUM-B-R). For alkali soluble AX the H samples had the lowest arabinose content. A single-tube preparative isolation procedure for starch-free barley fibre was used. Combined with NMR and GC this is a tool to produce defined fibre fractions for biological testing.