Showing papers in "Journal of Food Science and Technology-mysore in 1974"

Evaluation method of green tea grade by nitrogen analysis.

Abstract: An analytical method for Japanese Agricultural Standard of green tea was studied.First, one group of sencha (common green tea) including high, medium and low grade was subjected to chemical analysis as well as organoleptic test. The correlation coefficients between the content of main green tea constituents, i.e. total nitrogen, tannin (catechins), caffeine, water soluble matter, free reducing sugars and amino acids, and the scores of sensual evaluation, i.e. style, color, aroma, color of liquor and taste, were calculated. Among them that of total nitrogen was the highest on respective evaluation values.Next, the correlation coefficients between total nitrogen and evaluation values were investigated on other three groups of green tea including commercially packed tea or foreign produced tea.The total nitrogen content coincided significantly with the quality grade as to domestic tea, although it indicated only degree of style as to foreign produced one.

Functional Properties of Heat-induced Gel Prepared from Crude Fractions of Soybean 7S or 11S Proteins

Abstract: From defatted soybean meal, crude protein fractions were prepared by means of a conventional method to fractionate 7S and 11S proteins (7 SPRF, 11 SPRF), basing on the difference of precipitation behaviors with calcium salt between both. The functional properties of those protein fractions were then investigated. The results showed; 1) The optimum temperature to form heat-induced gel was around 70°C with fish jelly (surimi), around 80°C with 7 SPRF and more than 90°C with 11 SPRF. Comparing with 7 SPRF, 11 SPRF formed hard and tough gel, specially having higher tensile strain. 2) Functional properties of surimi were quite different between commercial products prepared during winter and summer. Addition of 11 SPRF to surimi prepared during summer could improve its properties. 3) Comparing with 7 SPRF, 11 SPRF showed higher water capacity, keeping gel-forming properties. 4) Comparing with 11 SPRF, 7 SPRF showed slightly higher emulsifying capacity.

Studies on Browning Reaction Products from Reducing Sugars and Amino Acids

Abstract: The nitrogen contents of the melanoidins purified from the heating mixtures of 2M D-xylose with 2M, 4M or 10M ammonia were 11.62, 12.47 and 12.86% respectively, and each melanoidin showed almost similar antioxidative activity on linoleic acid.On the contrary, the melanoidins purified from the heating mixtures of 2M D-xylose with 2M glycine, 2M ammonia, 2M L-arginine, 2M L-lysine or 2M L-histidine were divided into two groups on the nitrogen contents. One is a D-xylose-glycine and -L-lysine group containing about 6% of nitrogen and the other is a D-xylose-L-arginine, -L-histidine and -ammonia group containing the nitrogen of 11-12%. The latter group of melanoidin showed more inhibitory effect on the oxidation of linoleic acid than the former group, but the antioxidative activities were not always proportional to the nitrogen content in each melanoidin.In the comparison of the antioxidative activity of the melanoidin prepared from D-xyloseglycine with legal antioxidants at the same level of reducing power, the melanoidin exhibited more inhibitory effect on the oxidation of linoleic acid than BHA, propyl gallate or erythorbic acid. On the other hand, the comparison at the same level of weight showed that melanoidin has almost the same antioxidative activity on linoleic acid as BHA and a lower activity than BHT. Furthermore, a synergistic effect was observed in the combination of the melanoidin with BHA.

Noodle (Udon)-making Quality of Gamma-irradiated Wheats

Abstract: Noodle (Udon)-making qualities of wheat irradiated with 60Co-gamma ray at the dose levels of 20, 50, 100 krad were investigated with flours made from Japanese Norin-61 and with the one made by mixing American D.H.W., W.W. and Australian W.A. ·F.A.Q. in 3:4:4 ratio.Considerable damage of starch granules by irradiation were estimated from lowered viscosity in Amylogram and increased maltose value. This damage of starch resulted in increased material loss in cooking and inferior physical properties of cooked noodle. Increased dose level of irradiation reflected upon inferior score in sensory analysis, particularly with masticatory feeling. Inferior noodle-making quality of irradiated wheat were well correlated to dose level, where imported wheat was more sensitive than domestic wheat in terms of irradiation effects.

Struvite-like Substance separated from Soysauce prepared from Mieki

Abstract: The struvite-like crystal substances were separated from soysauce prepared from mieki.The crystals were identified as struvite seen occasionally in tuna can as the results of components analyses and infrared absorption spectrometry. The magnesium and phosporus contents of mieki and soysauce were determined and struvite formation at some pH values were discussed.Contents of these components were enough for crystalization of struvite in soysauce, but the most important factor was the pH value of the soysauce. It was necessary to prevent the struvite formation, to keep the pH value of soysauce under 6.0.

Antibacterial Substances in Green Tea Extract

Abstract: Antibacterial substances in hot-water extract (110°C, 15min) of a green tea product was investigated. The experimental results obtained were as follows.1. Antibacterial effects of the green tea extract appeared to be conspicuous on Vibrio metschnikovii and Alcaligenes faecalis. These bacteria were found to be about ten-times as sensitive as Staphylococcus aureus to the extract.2. The green tea extract was adsorbed to casein and the tannin fraction, which showed antibacterial effects, was eluted from the adsorbent with 90% aq. acetone. Five catechins were separated from the tannin fraction by paper chromatography and their contents were quantitatively determined. The minimum inhibitory concentrations (mcg/ml) of these catechins on V. metschnikovii were: epigallocatechin 20, epigallocatechin gallate 45, epicatechin gallate 45, gallocatechin 50, and epicatechin 75.3. Addition of caffeine at a concentration of approx. 1mg/ml showed a marked synergetic effect to increase the antibacterial titre of catechins (ca. 4mg/ml). However, caffeine itself (2mg/ml) had no antibacterial action.4. An aqueous solution containing the above five catechins and caffeine at the same concentrations as in the green tea extract showed a similar antibacterial titre to that of the extract.

Contribution of 11S and 7S Globulins of Soybean Protein to the Formation and Properties of Yuba-film

Abstract: To elucidate the functional properties of Yuba-film formed from 11S and 7S globulins of soybean protein, Yuba-like films were prepared from the solution of CIF (11S) and crude 7S glubulin (7S), and the conditions of film formation, stress, strain and other properties of the films were studied.The films from 11S were always stronger than those from 7S. Their stress and strain values varied with the changes of pH value of the solution, but in neutral range-normal condition of Yuba production, it was considered that 11S contributed to the strength of the film and 7s mainly to the hardness or brittleness.Adding 2-mercaptoethanol, N-ethylmaleimide or urea in the protein solution, formed films decreased the strength remarkably. It was seemed that SH_??_SS reaction was concerned in the strength of films. Wrinkles peculiar to Yuba-film might have something to do with SS-linkage in the film proteins, because they appeared on 7S film, but not on 11S film, and they did also on the latter when it was prepared adding N-ethylmaleimide.

The Effects of Essential Oils and Spice Extracts on the Prevention of Slimy Spoilage of Wieners

Abstract: The essential oils, methylene chloride extracts of some spices and some citrous oils were employed.Citrous oils did not prevent slimy spoilage, but these constituents, N-methylanthranilic acid, octylaldehyde and citronellal, showed a little preventive effects. The essential oils of celery, cinnamon and cumin, and the extract of dill showed the considerable effect to prevent the slimy spoilage. The combined effects with sorbic acid or lysozyme were observed in the case of many spice essential oils and extracts.

Studies on groundnut protein concentrates prepared by alcohol and acid washing of the defatted flour.

Abstract: Defatted groundnut flour was extracted with 80% ethanol, 80% isopropanol and 0.05 N HCl with a view to obtaining bland protein concentrate. The total soluble solids extracted were about 15% with the alcohols and about 22% with acid. The acid-extracted residue contained about 67% protein and showed a very low trypsin inhibitor activity. All the 3 extracted samples had aflatoxin levels below detectable limits while the original sample had 38 parts/billion. The nutritional value of the protein measured as PER remained unaffected in the extracted residues.

Content of Fungal Body in Soy Koji

Abstract: One of the characteristics in soy sauce manufacture is that the whole raw materials, wheat and soybean, are changed together into koji fully grown with. Aspergillus sojae. Therefore, not only from the enzymatic point of view, but also the amount itself of fungal body should be taken into account for preparation of soy mash.In the present paper we tried to know at least an approximate content of fungal body, mycelia plus conidia, by using the specifically high content of glucosamine in mold. Glucosamine level in raw materials was obtained as 0.95% in dry basis, whereas in fungal mat 9.9%. Fortunately, the contents in mycelia and in conidia were fairly the same.Glucosamine level was determined in each soy koji prepared by culturing for different days and the content of fungal body was calculated as: 3-days koji; 13%, 4-days koji; 17%, and an old 10-days koji; 28%.

Antioxygenic Substances in Red Pepper

Abstract: In spite of the unstability of carotenoid pigments, the color of the red pepper, Capsicum annum, is preserved for a long time even in the dried state. This suggests the occurrence of some antioxygenic substances in Capsicum.In order to determine the effective compounds, Capsicum was extracted with chloroformmethanol (2:1) and water and the antioxidant activity of each fraction was estimated by oven test method.The antioxygenic substances were found in lipids fraction and the active substances were divided into two fractions by silicic acid column chromatography. By thin layer and gas liquid chromatographies, antioxygenic substances in Capsicum were identified as α-tocopherol and cap- saicins. Capsaicins were known as the pungent principles in Capsicum, but the antioxidant activity has not been reported.It was also proved that both of these substances were effective to the preservation of the carotenoid pigments of Capsicum (capthanthin and capsorbin).

Goitrogenic Substance in Rapeseed

Abstract: The screening tests on the myrosinase-like activity of intestinal bacteria of chickens were made employing the cultural analysis of intestinal flora.The tests were made on 68 healthy chickens. A progoitrin prepared from rapeseed was used as substrate, and goitrin in biological fluids was assayed by the spectrophotometry.In the chickens fed with rapeseed oil meai inactivated its myrosinase by cooking, goitrin was detected in the middle intestine, rectum, and blood.The incubation tests indicated that the caecal contents consistently hydrolyzed progoitrin to goitrin, and the middle intestine contents and recrum contents were occasionally active. But, in those of other portions, the myrosinase-like activity could not be found.Moreover, bacteria with myrosinase-like activity were isolated from the caecal contents and caecal feces. These may include various members of the intestinal flora, such as Catenabacterium, Bifidobacterium, Bacteroidaceae, Streptococcus, and Enterobacteriaceae.Thus, these studies.indicated that progoitrin is hydrolyzed by living bacteria which are normal inhabitants of the lower alimentary tract in chickens.

Effect of storage time and γ-irradiation on the development of di-n-propyl disulfide from onion bulbs

Abstract: Onion bulbs of unirradiated and irradiated with 4.2 and 8.1 Krad by 60Co gamma rays were stored at 4° and 10°C for five months, and the relationship between the sprouting and the amounts of di-n-propyl disulfide (DPDS) developed from the sliced onions was investigated. The amount of DPDS increased apparently along with the sprouting. The sprout inhibition with the irradiation was appeared to suppress the development of DPDS.

Studies on Spray-dried Citrus Unshiu Juice

Abstract: Citrus Unshiu juice with various contents of pulp (10 to 25%) were dehydrated by spray drying to form powder. The equilibrium moisture contents were determined by the saturated salt solution-desiccator method at 25°C.The equilibrium moisture contents of the spray-dried Citrus Unshiu juice decreased at low relative humidity, whereas sharp increase was seen at high relative humidity. The equilibrium moisture contents of the powder became larger with decreasing the contents of pulp.As the relative humidity increased, the powder required longer period to reach the equilibrium moisture contents.The unilayer adsorption water (4.8 to 6.1%) and adsorption area (171 to 220mm2/g) of the powder became larger with decreasing the contents of pulp.Isosteric differential heat of adsorption of the powder was 12.2Kcal/mol at low equilibrium moisture contents.

Emulsifying Property of Egg Yolk, Especially as to the Effect of Salt

Abstract: Effects of salts on the emulsifying properties of whole yolk and yolk proteins in the watercotton seed oil system were investigated. The results are as follows:1) HLB of egg yolk obtained from the spreading coefficient was 12.4.2) The strength of emulsion stabilizing power of yolk protein fractions were in the order of phosvitin-lipovitellin fraction (PvLv)>water soluble fraction (WSF)>low-density fraction of granule (LDFG)>low-density fraction.3) The stability of emulsion by yolk and yolk protein fractions changed due to salt concentration, and had a peak at 0.025-0.1 M of NaCl. Yolk, PvLv and Lv had another peak of stability at 0.2-0.4 M of NaCl.4) CaCl2 had a lower stabilizing ability than NaCl, and NaSCN had as high stabilizing ability in a lower concentration as NaCl.5) The interfacial tension and viscosity of the emulsions by yolk protein fractions decreased in the order of PvLv>LDFG>LDF>Livetin, but did not agree with their emulsion stabilizing power.

Studies on Sulfur Stain of Internal Wall of Cans

Abstract: The existence of the unknown substance (s) was suggested, which was entirely different from so-called "corrosion factors" such as nitrates, anthocyan pigments, cysteine and cystine and presumably plays the main role in the corrosion reaction in canned asparagus.White asparagus was extracted with 75% ethanol and the fractions with ion exchange resins and ethereal extraction were examined as to the corrosion activities.Both the sulfur-staining and corroding activities were found in the effluent from Dowex 50W×8 (H+ form). Further fractions with Amberlite IR-45 (OH- form) treatment showed considerable activities of sulfur stain and corrosion.By paper chromatograms of the hydrolyzates of the fractions, citric and tartaric acids were detected, which were not detected on paper even after extraction of the unhydrolyzed fraction with ether for 120 hours. The hydrolyzates and one of the ethereal extracts contained significant amount of glutamic acid.It is assumed that at least one of the sulfur-staining and corroding factors in the fresh plants is the loose conjugate of glutamic acid and the organic acids. Results obtained from the fractionation studies also strongly indicates that sulfur containing carbohydrates and organic acids are involved in the sulfur-staining reaction of the internal wall of canned asparagus.

The Effects of Sugar Alcohols on Oxidative Stabilities of Fats and Oils

Abstract: The antioxidative activities of glycerol, xylitol, sorbitol and maltitol were investigated against the autoxidation of linoleic acid in aqueous system and lard added to biscuits.Although glycerol, sorbitol and maltitol accelerated the autoxidation of linoleic acid in the range of 0.008-0.8M, xylitol exhibited the antioxidative activity at the same concentration.However, glycerol, xylitol, sorbitol and maltitol showed remarkable inhibition on the autoxidation of lard in biscuits. Especialy, induction period of lard was prolonged about 300 and 500 days with maltitol and sorbitol at 10% level respectively.Synergistic effect did not exist in a combination of xylitol with tocopherol.

Rapid Method to Determine Lactic Acid in Fermented Milk by Gas Chromatography

Abstract: A rapid and simple method of gas chromatography was studied to determine lactic acid in fermented milk.The column employed was PEG-6000(10%) on terephthalic acid solid support (1.5m long glass column), which permits separation of lactic acid without derivatizing it into a volatile compound.In this method it is not necessary to extract, esterify or trimethyl-silylate the sample. The column temperature was programmed from 120°C to 190°C at 6°C/min. The lactic acid was identified by a GC-MS combined system.The fermented milk sample was added with sulfuric acid to be 0.1% (V/V) and introduced into the gas chromatograph to determine lactic acid quantitatively.This method gave good quantitativeness for lactic acid and a long life for the column.

Chemical and Color Changes in Tomato Juice by Heating during Processing

Abstract: Teneur en amylose, proprietes organoleptiques et texture de tybercules et de farine de manioc de sept varietes avant et apres grillage

Time-temperature Tolerance for Keeping Quality of Fresh Fruits and Vegetables

Abstract: We have investigated the time-temperature tolerance of various fresh fruits and vegetables during low temperature storage at above freezing temperature in relation to their marketing qualities. This report describes the effects of various temperatures and the fluctuation on the quality of spinach and celery during the storage.1. It was recognized that freshness, leaf color and ascorbic acid content of spinach were strongly influenced by storage temperatures. The period of keeping marketing quality of stored spinach was about 35 days at 1°C, about 15 days at 6°C, and about 3 days at 20°C. The fluctuation of the temperature during storage accerated the deterioration of the quality, and it depended on the maximum temperature of the fluctuation. Ascorbic acid content of stored spinach decreased rapidly at 20°C but decreased gradually at 6°C and 1°C, The fluctuation of the temperature during storage resulted in a rapid decrease of ascorbic acid.2. In order to keep freshness and higher content of reducing sugar in stored celery, the constant low temperature of 1°C was required immediately from the harvest day. The good quality was kept for 7 weeks at 1°C, for about 25 days at 6°C and for about 5 days at 20°C. The patterns of gas chromatogram of the volatile compounds of celery were significantly different between 20°C or 6°C-treatment and 1°C-treatment.3. Thus, it was shown that for the keeping quality of spinach and celery they should be kept at nearly 1°C immediately after harvest and during the subsequent storage.

On Decrease of Redispersibility of Dried Soybean Protein Powder during Storage Period

Abstract: FUKUSHIMA et. al. reported about the mechanism on the rapid decrease of the redispersibility of soy milk after drying in the manufacturing process. There is another trouble which occures during the storage of dried soy milk or soybean protein powder. The proteins contained in it are sometimes insolubilized during the storage of three months or so at room temperature or during oversea transportation. The cause was traced and it was concluded that the insolubilization was probably due to interactions of protein molecules by their SH groups or hydrophobic groups, when products were under powdered state. The reactions were accelerated when products had comparatively high moisture contents.

Sprout Inhibition of Onions by Ionizing Radiation

Abstract: The dormancy period of onion, Cult. "Sapporoki" was about one month after harvest. Sensitivity of onion to irradiatian gradually decreased after the dormancy period accompanied by growth of inner bud. At this stage, inhibition of sprouting could not be achieved when the same was irradiated after three months of harvest. Complete suppression of sprouting was observed in onions irradiated with 3 to 7 Krad during the dormancy period.Usually, harvested onions are dried for two weeks before irradiation. Inhibition of sprouting and keeping quality were attained with the dose of 3 to 7 Krad when freshly harvested oaions were irradiated either before or during the drying treatment for storage.Irradiation period could be extended by low temperature storage of onion after harvest. Growth of inner bud suppressed at 3-5°C even after three months of storage and the length of inner bud was similar to that of one month old onion. Thus, sprouting was inhibited by irradiation and apical dominence observed for three months from the harvest date when onions were stored at low temperature.Browning of buds was observed in irradiated onions during storage. This was prevented by low temperature storage and such onions have retained good market quality for one month when transferred from low temperature to ambient temperature.

Studies on the Antioxidant Activities of the Derivatives of Sulfur Containing Amino Acids on Oils

Abstract: Etude des aptitudes technologiques de gomme guar, a differentes concentrations, de gelatine et d'alginate de sodium ; effet sur la viscosite, les proprietes rheologiques et organoleptiques des cremes glacees

Studies on Quality Index of Canned Agricultural Foods

Abstract: This study was designed to evaluate storage life from the behaviour of carbonyl compounds of canned mandarin oranges during storage. The results of thin-layer chromatograph- densitometric tracing showed that the percentage of 5-hydroxymethyl furfural (HMF) increased during storage. Therefore, HMF content as an index for quality was determined by p-toluidine/barbituric acid colourimetry. The content increased during storage especially at higher temperature and correlated well with organoleptic evaluation. Samples contained HMF above 5mg (%) gave low organoleptic. In commercial products, such high level of HMF was achieved after 3 to 5 years storage.