Inflation (swelling spoilage) of packaged foods is often caused by gas production of heterofermentative lactic acid bacteria. We have investigated the effects of various additives which may suppress the growth of the bacteria on the gas production, and in this report, the effect of monoglycerides and spices are described. Monocaprylin, monocaprin and monolaurin suppressed the gas production when they were added into liquid media at 0.1-0.3%. Monocaprin had the highest effect of the three. However, the effects of the monoglycerides were reduced after they were heated with potatostarch at temperatures above 65°C, which is a little higher than the gelatinization temperature of the starch. Clove, rosemary and garlic also suppressed the gas production at higher concentrations than 0.04%, 0.2% and 0.1%, respectively. Furthermore, the addition of any one of the spices even at a lower concentration than the effective one induced the combined preservative effect with monocaprin even in the presence of the starch.

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The Aspergillus oryzae N-2 which was isolated from 26 commercial Koji starters f or miso and soy sause produced a lot of PGAase which hydrolyzed γ-poly glutamic ac After solid fermentation of A. oryzae N-2 with wheat bran for 3 days, the crude enzyme was extracted and fractionated by ammonium sulfate (60-95% saturation). The partial ly purified enzyme was obtained by dialysis of the fraction against tap water. The optimum temperature and pH of the enzyme were 40°C and 4.5-5.0, respectively, using γ-poly Lglutamic acid as a substrate. The enzyme cleavedgb γ-poly L-glutamic acid signifi cautly and γ-poly D, L-glutamic acid partially. γ-Poly D-glutamic acid was, however, not hydrolyzed. hydrolyzed. γ-poly L-glutamic acid as a hydrolyzate determined by paper chromatography.

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Recently utilization of far infrared radiation attracts public attention on the processing of food industries. In this paper, drying experiments of potato were carried out, using some far infrared radiation heaters. Moreover, the relation between supplied electric power and surface temperature of heaters was discussed. And the following results were obt ained. (1) In far infrared heaters which were used in our experiments, the heater with the strongest emissive power provided the largest drying rate. (2) When supplied electric power to far infrared heaters was strong, temperature of the sample was high, drying rate became large, and constant-rate period was short. When supplied electric power was weak, const ant-rateperiod became long. (3) Surface temperature of far infrared heaters was lower than that of black body, because the Joule's heat is deprived from the surface of the heater to the surrounding air by natural convection.

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The composition of carotenoids in three different root colored carrot (Daucus carota L.) cultivars was studied. The carotenoids were separated by column and thin layer chromatography and identified by order adsorption affinities on the column and by their absorption spectra. The contents and kinds of carotenoids were as follow; (1) The red root carrot cultivar 'Wase Kintoki' and 'Honkou Kintoki' contained lycopene (80-140μg/g) as the major pigment; a small amount of xanthophylls, phytofluene, α-carotene, β-carotene and ζ-carotene were present. (2) The major pigments in orange root carrot cultivar 'Kuroda Gosun' were α-carotene (17-25μg/g) and β-carotene (27-33ug/g); phytofluene, ζ-carotene, xanthophylls and lycopene were also present in small amounts. (3) In the yellow root carrot cultivar 'Shimaninjin', the main pigment was xanthophylls (12-16ug/g); a slight amount of phytofluene, α-carotene, β-carotene and lycopene were present.

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Grain sorghum (Sorghum bicolor (L.) Moench) is one of the most important crops in the world. It is not consumed as food, but used as feed especially in advanced countries. Its appearance, nutritional value and palatability should be improved for human consumption of the grains. For the purpose of such improvement, the extrusion tests of the grain sorghum were carried out here using a simple single-screw extruder. As a pretreatment of grain sorghum for extrusion, whitening by the abrasive milling machine to the yield of 70-80% was effective to improve expansion degree and decrease the polyphenol content. Good expansion was attained when the moisture content of the material was adjusted to 14%. The various high-protein ingredients were tested as additives in order to improve the nutritional value of the extruded products. Three ingredients, gluten-meal, defatted soyflour and dried yeast, were selected from the viewpoint of expansion degree. Among them, dried yeast was most attractive because it enriched most effectively extruded products with lysine and vitamin B₁. Much differences in expansion degree were found among the extruded products of the grain sorghum added with 10% of yeast cells commercially available in Japan, and brewer's yeast was found to be the most suitable. Addition of the brewer's yeast to the grain sorghum improved not only nutritional value but also expansion degree of the extruded product.

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The contents of potassium, sodium, calcium, magnesium, iron, copper, zinc, manga nese cadmium, lead and mercury in 64 herbs were determined by atomic absorption metho d and arsenic was determined spectrophotometrically. The values of these elements in v arious herbs are as follows; K: Below Detectable Level (B.D.L) -6.5%, Ca: B. D. L. -2.8%, Na: B. D. L. -1110mg/100g, Mg: 38-994mg/100g, Fe: 3.788mg/100g, Cu: B. D. L. -93.3mg /100g Zn: B. D. L -27.9mg/100g, Mn: B. D. L. -197mg/100g, Cd: B. D. L. -0.9ppm, Pb: B. D. L. these results, sodium contents of sage and deer's tongue and copper contents of hops were found in high concentration significantly compared with the others, but there were not remerkable differences in mineral contents among the other herbs.

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For measuring the texture of cooked rice, blended of more than two different kinds ofrice, an improved measuring method by texturometer was examined to reduce variation ofmeasured values and to increase reproducibility. Cooked rice samples of 20 grams of milledrice were used in the measurement. The results are as follows: (1) On measuring 3varieties of rice, different trends in the variations (mean value, standard deviation andcoefficient of variation) were observed. (2) Samples with uniform grain size prepared bysieving (slot perforation of over 2.0mm and through 2.1mm) could not reduce the variationof the measured value any more than the unprocessed original samples. (3) As to thenumber of measurements, the mean value of the 4 times measurements were in the estimaterange of population means by the 12 times measurements. Therefore, it is assumed that the4 times measug method using dual arms and 4 times measurements on the unsieved wholesamples is regarded as sufficient. As to the relation between the characteristics shown bytexturometer and palatability evaluation on the single variety (unblended) of cooked rice, asignificant correlation was recognized on the adhesiveness (A₃) and hardness/adhesiveness(H/A₃). Tendency for a large variation in the palatability evaluation and rather smallvariation in the characteristic values by the texturometer were observed.

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A new dough testing system was designed and constructed to measure automatically gas production in fermenting doughs. This system is in principle a manometer measure d with rotary encoder, and a microcomputer controls data acquisition and analysis at su itable intervals. This instrument measures the amount of total gas produced with time a nd/or the amount of gas retained in the dough by evaluating the volume absorbed by an alka li solution of the gas escaped from the dough. The maximum number of channel operated by the microcomputer is 48 and this channel to channel precision is below 2% or 0.2ml. The microcomputer which is operated by a program written in BASIC provides the patte rn of CO₂ production per 5min and the point at which the dough starts to lose CO₂. For thi s purpose, several data processing subroutines are involved in the program; the amount of t otal and part of gas at every 5min, making graph and running average. As examples, some measurements were demonstrated, The pattern of gas production from sponge dough was similar to that of Zymotachygraph. Correlation coefficients were 0.91-0.98 betw een CO₂ production measured with this instrument and expansion of bread and sweet dough measured with the cylinder method. Coefficients of variation of the gas production betwee n 12 channels were generally stable after 60min. The performance and drawbacks of the present system are discussed. This instrument is now commercially available as Fermograph (ATTO Co., Ltd., JAPAN). (Received Aug. 11, 1987)

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Volatile constituents of the two pickled products, Nozawana-zuke and Hiroshimanazuke were studied by GC and GC-MS analyses after their fractionation into acidic, basic, phenolic and neutral fractions. The three fractions except the basic which had almost no odor were subjected to identification of the constituents, and 57 compounds were identified in all consisting of 3 carbonyls, 8 esters, 2 sulfides, 4 alcohols, 7 phenols, 7 nitriles, 8 isothiocyanates, 17 hydrocarbons and an acid. A little difference was observed in the kinds of the volatiles between the two pickled products. Most of the volatiles were found in the neutral fractions, where the degradation products of glucosinolates, namely, isothiocyanates and nitriles were the major together with some methyle sters of lower molecular fatty acids (C₁₀-C_l4).

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Hydroxybenzoic, and hydroxycinnamic acids of free, glucosidic, and ester forms were obtained separately from fresh leaves of six cruciferous vegetables and analyzed by GC and GC-MS. Three hydroxybenzoic acids (p-hydroxybenzoic, vanillic, and protocatechuic acids) and eight hydroxycinnamic acids (cis-, and trans-isomers of p-coumaric, ferulic, caffeic, and sinapic acids) were identified in all the vegetables used, of which cis-, and trans-sinapic acids were the most prominent and trans-ferulic acid was next abundant in each phenolic acid fraction of the vegetables. The hydroxybenzoic acids were relatively higher in amounts in the glucosidic fractions. On the other hand, most of the hydroxycinnamic acids were found in the alkaline hydrolyzates of each vegetable extract, indicating that the hydroxycinnamic acids are mainly contained as esters.

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