RHEOLOGY AND THERMAL PROPERTIES OF SYRUPY COMPOSITES OF SACCHARIDES AND MILKFAT

Viscous syrups with between 20 and 34% moisture were made from homogenized slurries of sugars, nonfat dry milk, anhydrous butteroil and emulsifiers. Homogenized mixtures were condensed under vacuum at 45C for 35 min, to form ordered structures with a syrup-like consistency. Complex viscosity determined through dynamic spectrometry increased with increasing fat content. At low frequency, high fructose corn syrup and maltose-based syrups showed more solid-like behavior (G" > G") while the sucrose-based syrup was more liquid (G" > G'). Thermal analyses showed all composites to have a uniform melting range (95–140C), whereas the original components melted in the range 20–200C. The rheological and thermal properties suggest that these syrups could be useful confectionery ingredients.     

STUDIES ON COMPARATIVE MALTING CHARACTERISTICS OF SOME TROPICAL CEREALS AND MILLETS

Malts prepared from some of the tropical cereals and millets were evaluated for their suitability in weaning food formulations. Pearl millet and finger millet malts exhibited high α-amylase activity within 2–3 days of germination, while maize, sorghum, wheat and triticale malts showed high enzyme activity after 4–5 days of germination. Malting drastically lowered the paste viscosity of cereal flours especially millet. Finger millet malt had desirable flavour and taste besides high amylase activity. Wheat and triticale malts also had acceptable flavour. Rice malt was bitter and pearl millet malt developed rancid odour and bitterness within a week after preparation.     

小米营养乳生产工艺

以营养丰富的小米为原料，对小米乳饮料的生产工艺、配方及产品质量进行研究，指出了酶反应最佳条件、稳定剂对产品质量的影响及工艺条件对小米营养乳饮料稳定性的影响，得出了色、香、味及组织状态俱佳的小米营养乳饮料。     

PROCESSING OF FOXTAIL MILLET FOR IMPROVED NUTRIENT AVAILABILITY

Foxtail millet grains were soaked in distilled water (1:5, w/v) for 12 h at room temperature, dehulled; dehulled and soaked; and dehulled, soaked and cooked in distilled water (1:3, w/v), and the effects of removal of polyphenols and phytate on the in vitro protein digestibility (IVPD) and availability of iron and zinc were measured. The results showed that polyphenols and phytate were decreased significantly up to 50.92 and 49.89%, respectively. The IVPD, however, increased up to 38.71%. The iron and zinc contents decreased up to 18.79 and 18.61%, respectively, but the ionizable iron and zinc were increased up to 55.45 and 80.18%, respectively. This indicated the suitability of simple processing techniques for improvement of availability of nutrients from foxtail millet.     

INDICATOR AND PATHOGENIC BACTERIA IN GUACAMOLE AND THEIR BEHAVIOR IN AVOCADO PULP

The presence of some indicator microorganisms and pathogenic bacteria in guacamole sampled from restaurants and street vendors, and the behavior of Salmonella spp. , Staphylococcus aureus, and Escherichia coli O157:H7 were studied in avocado pulp. Coliform, yeast and mold populations showed a wide dispersion, in agreement with the diversity of sanitary conditions observed among places sampled. The frequency of Salmonella spp. , Listeria monocytogenes, and E. coli were 1.3, 16.0, and 60.0 %, respectively; with higher numbers among street vendors. Populations of E. coli ranged from 29 to 3800 NMP/g and S. aureus from 2.95 to 5.35 log CFU/g. Thirteen out of 16 hemolytic L. monocytogenes strains were pathogenic for mice. In avocado pulp Salmonella spp. and E. coli O157:H7 showed a lag phase close to 3 h, and a generation time of 54 min and 1.23 h, respectively. No growth of pathogens was observed in avocado pulp stored at 4-7C.     

TRENDS IN SUPPLY AND DEMAND FOR MILK AND DAIRY PRODUCTS IN THE UK

The paper examines the changes in yields and dairy cow numbers in recent years and considers the likely economic prospects for investment in modern dairy units. With full Community prices applied in the UK at a realistic rate of exchange, dairying would be very profitable. In spite of the setback between 1973 and 1975 the milk output objective of the Government's White Paper 'Food from Our Own Resources' should be reached in the first half of the 1980s. Liquid milk consumption will be fairly stable in the future, but with the higher prices under the Community régime the butter market will contract. A modest increase in cheese consumption will continue. Higher milk production in the UK and a reduced market will increase self-sufficiency. In spite of the European surplus in the dairy sector the competitive strength of the UK industry at Community prices is substantial and it is economically right for it to expand.     

CHANGES IN THIOL AND DISULPHIDE CONTENTS IN BARLEY EMBRYOS DURING DORMANCY AND AFTER-RIPENING

During after-ripening, moistened embryos of Balder barley were initially unable to release glutathione and cysteine from peptides and alcohol-soluble proteins already present in the embryo; later they were able to do so. When dormancy was broken by soaking the grains in gibberellic acid, the embryos rapidly released glutathione and cysteine, immediately after harvest-ripeness. A good correlation was found to exist between the sum of the amounts of glutathione and cysteine found in the embryos after 24 hr. soaking and the percentage of grains germinated in three days.     

鞣制材料及成品革中甲醛的研究

甲醛通常是用于合成鞣剂制备的一种基本原材料。即使目前的工业生产过程采用电脑进行控制,但也可能在最终产品中含有甲醛。甲醛是一种对于人体或其他生物极具危害性的物质。因此,在一些强制性条文中明确规定了这种物质在成品革中的最大含量以及测定其存在所应参照的分析方法。然而皮革中甲醛含量的测定方法不能完全适用于鞣剂产品中甲醛含量的测定,实际上会有很多因其他物质的存在而产生的干扰因素。所以不可能把鞣剂材料中甲醛含量和成品革的甲醛含量之间进行比较。论文对以上这些因素的数据进行了研究,旨在降低鞣剂产品及其所生产皮革中的甲醛含量。     

VARIATION IN pH AND LACTATE LEVELS IN MALTS

Malt pH, defined as the pH of worts prepared by the Institute of Brewing Methods of Analysis, was examined in commercial malts from a single malting plant over four crop years, 1990 to 1993. Batch to batch variability was found, in addition to a distinct pattern within two of the years, with a gradual decrease in the winter months following commencement of malting of the new crop barley, followed by a subsequent increase in the late summer. Variability in pH and the longer term trend were not related to any measured processing variables or characteristics of the barley used for malting. Possible reasons for the differences in pH were examined and a negative relationship between malt pH and wort lactate content was demonstrated in a selection of malts from two crop years. A method is proposed for extraction and purification of lactate directly from malt and using this method it was shown that lactate in wort derives mainly from malt with only small amounts being produced during mashing.     

AFLATOXIGENIC ASPERGILLI IN FOODS AND FEEDS IN UGANDA

Studies conducted during the sixties and the seventies on food crops in Uganda showed that the populace was exposed to consumption of aflatoxin-contaminated foods. These studies also linked the highest incidence of liver cancer in the world to the presence of high levels of aflatoxins in the food and beverages. After a lapse of a decade, it was of interest to investigate the occurrence of aflatoxins and aflatoxigenic fungi in staple Ugandan food crops and poultry feeds derived from these foodstuffs. A simple, rapid and reproducible procedure was used. The procedure consisted of growing or culturing feed grains on a selective medium, Aspergillus flavus/parasiticus agar (AFPA) followed by screening for aflatoxin producing fungi on a coconut agar medium (CAM) under UV light with a subsequent confirmatory screening method for aflatoxin production by the fungi in pure culture. Fifty-four samples consisting of corn and peanuts, soybean and poultry feed were analyzed for content of aflatoxigenic. A. flavus/parasiticus and 25 of the samples were also screened for aflatoxins B₁ and G₁, zearalenone, sterigmatocystin, ochratoxin A, citrinin, vomitoxin, and diacetoxyscirpenol (DAS). Aflatoxigenic A. flavus/parasiticus was detected from the majority of corn (77%), peanuts (36% human food and 83.3% animal feed) and poultry feed (66.6%). but not from soybean samples. Two samples out of 25 contained detectable levels of aJatosin B, (20 ppb). For the jirst time other mycotoxins, zearalenone (3 samples) and vomitoxin (2 samples) were detected in corn from Uganda.     

NITRATE AND NITRITE CONTAMINATION IN VEGETABLES IN CHINA

This paper reviews recent studies of nitrate and nitrite contamination in Chinese vegetables. Nitrate and nitrite contamination is very serious and increases the amount of nitrogenous fertilizer applications. Factors influencing nitrate and nitrite contamination in vegetables are analyzed and discussed.     

THE IN VIVO AND IN VITRO DEGRADATION OF BARLEY AND MALT STARCH GRANULES

The susceptibilities to amylolytic hydrolysis of the two different types of starch granule in barley and malt have been investigated. The large and small granules from both germinated and ungerminated grain were subjected to the sole action of malt α-amylase under conditions which otherwise simulated those of a conventional infusion mash. Large starch granules from barley are hydrolysed at a slower rate than those from malt. The faster conversion of the latter is attributed to prior modification of the starch granule structure during germination. The small granules from barley are extremely resistant to attack by α-amylase and even pre-cooking does not appreciably increase their susceptibility to amylase attack. Although the small starch granules from malt are less susceptible than the corresponding large granule fraction, they can be hydrolysed to a greater extent than can the small granules from barley. The increased susceptibility of small granules from malt is probably due to the partial removal of their protecting surface layer of protein. Although during malting the small granules of barley are hydrolysed more rapidly than the large granules, the situation is reversed during mashing. Very little loss of extract can be attributed to the enzymic resistance of small starch granules in all-malt mashes. If raw barley is used in the grist, substantial amounts of small starch granules may remain in the mash.     

NITRATE AND NITRITE CONTAMINATION IN VEGETABLES IN CHINA

This paper reviews recent studies of nitrate and nitrite contamination in Chinese vegetables. Nitrate and nitrite contamination is very serious and increases the amount of nitrogenous fertilizer applications. Factors influencing nitrate and nitrite contamination in vegetables are analyzed and discussed.     

GUSHING PROMOTERS AND SUPPRESSANTS IN BEER AND HOPS

The fatty acids present in beer and hops were found to have pronounced effects on gushing, some at concentrations of I ppm or less. Saturated fatty acids are weak gushing promoters, while unsaturated acids are powerful suppressants. A parallel structure-activity correlation also exists in a series of α-acid derivatives and their analogues. Compounds with the unsaturated side-chains intact showed either weak suppressant activity or none at all. Loss of carbon-carbon unsaturation through hydrogenation or cyclization produced powerful gushing promoters, but reduction of carbonyl unsaturation as in ρ-isohumulones, or loss of side chains as in humulinic acids had no effect on gushing. Promoter and suppressant effects of the compounds tested were non-specific and mixtures of unsaturated fatty acids suppressed all instances of gushing, whether natural or artificially induced. The results indicate that beer normally contains both gushing promoters and suppressants, and gushing may sometimes be due to an imbalance between them.