Changes within Lactobacillus and Bifidobacterium species

Laboratory rats with a gut flora unambiguous free from Bifidobacterium revealed three days after an application of a lactose-rich food a dominating Lactobacillus plantarum flora. Up from this date, Bifidobacterium could be detected for the first time. At the beginning, there was to be observed merely B. adolescentis and B. pseudolongum, at the 5th to the 10th day B. bifidum supervened. Finally this species together with B. infantis was dominating. With in vitro experiments, by a systematic modifying of the medium changes from Bifidobacterium species typical to faeces from infants to such species only to meet in faeces from adults could be observed only after a long time of cultivation.     

PROPOSALS FOR THE EFFICIENT AND ECONOMICAL USE OF HOPS IN BREWING

The hop lupulin glands, which contain the essential oils and resin acids, can be separated effectively from the bulky and worthless bracts and residues in a mechanical process which avoids solvent contamination. The separation is accomplished in an air stream through a centrifugal sifter after the lupulin has been rubbed off in a disc pin mill. The separated lupulin can be broken open by grinding in a colloid mill and used to obtain a dry hop aroma in beers by an ‘instant’ process. The lupulin can be used to bitter beers either directly in the copper or in a pre-boiling process. It can also be used in an aqueous extraction process to yield, nearly quantatively, pure and separate extracts of the α- and β-acids. The α-acids can then be isomerized almost quantitatively and the β-acids can be oxidized to give a 50% yield of hulupones. The hop residues, when boiled with wort, give an approximately 50% utilization of the remaining α-acids. These isohumulones can then be enhanced by those obtained from the extracted α-acids and the bitterness can be supplemented by the hulupones obtained from the β-acids. Overall, this process is calculated to give a bitterness utilization equivalent to 87% calculated on the original α-acids.     

Dietary factors affecting trace element bioavailability from human milk, cow's milk and infant formulas

Bioavailability of trace elements is affected by the type of diet in which they are presented. In general, absorption of the elements iron, zinc, copper, manganese and selenium appears to be higher from human milk than from cow's milk or cow's milk formula while absorption from soy formula appears to be lower than from milk-based products. The effects of individual components such as protein source, carbohydrate, phytate, organic acids and other cations on absorption need to be assessed and the integrated effects of individual dietary components need to be assessed in the intact diet. While ideally absorptive studies should be performed in human infants, there is a need for developing useful and valid models for assessing trace element bioavailability. Increased knowledge about trace element absorption from different infant diets and the factors involved will lead to a better understanding of trace element requirements of infants. This will help in the suggestion of ways to improve means of supplementation.     

Isolation of amylolytic system of Aspergillus oryzae by sorption on DEAHP amylum.

Conditions of effective sorption of amylolytic enzyme from a solution or from fermentative liquid on DEAHP amylum were studied. Isolating action is in a direct dependence on the relation between activity and amount of DEAHP amylum, the curve of this dependence was illustrated. The enzyme can be released by elution or adsorbate can be used in a pulverised from. In the conclusion of the work laboratory isolation technique is described.     

酯交换法制备生物柴油研究进展

生物柴油是一种发展迅速的可再生能源,它可以作为传统石化柴油的良好替代品。动植物油、废弃食用油和植物油精炼皂脚都可以作为原料来制备生物柴油。酯交换法是最常用的生物柴油制备方法,目前根据选用催化剂的不同酯交换法又可以分为均相催化法、非均相催化法、脂肪酶法以及超临界法。均相催化法已经研究的比较成熟,广泛应用于工业化生产。非均相催化法、脂肪酶法可以较好地解决催化剂与产品的分离问题,是目前的研究热点。超临界法对原料要求较低,后处理过程简单,有较大的发展潜力。     

Corneal structure,transparency, thickness and optical density (densitometry), especially as relevant to contact lens wear—a review

Clinical instruments using Scheimpflug image-based methods to obtain optical sectional images of the cornea have been introduced in recent years along with proposals that it should be possible to routinely and reliably measure the optical density (referred to as the densitometry) of the human cornea in situ. Such a concept is reviewed from the perspective of what might be considered as the basic principles underlying the understanding of corneal transparency (from the 1950’s) and the progressive changes in these ideas from subjective slitlamp-based clinical observations from the late 1960’s, especially in contact lens wearers. Much more has been learned about the overall macrostructure (including corneal thickness) and the ultrastructure of the cornea from contemporary studies in the 1990’s, and these aspects of the cornea will be reviewed alongside consideration of the methods of assessing the optical characteristics of the cornea in the living eye. From these perspectives, in this review systematic consideration will be given to what objective (quantitative) output one of these Scheimpflug-based systems provides and how this information might be actually related to corneal transparency characteristics that might be observed clinically, particularly after long-term contact lens wear.     

金属过滤器韵不完全清洁对聚合物生产厂操作成本的影响

用户和保养机构需要使用大量的清洁程序来去除聚合物过滤器中金属过滤网上的残余聚合物和添加物。探讨了清洁过程的效力对聚合物生产厂成本的影响，涉及清洁过程的效率、产品质量和过滤器替换品的成本。以历史实际数据为基准。     

Formation of plastein gels from peptic digests of field bean protein isolates

Peptic partial hydrolysates of a different hydrolysis degree were prepared from horse bean protein isolate and used for the plastein reaction with thermitase. Whilst unsoluble products were formed from partial hydrolysates of a hydrolysis degree above 60%, plastein gel could be obtained from a less intensely split basic material. By gel chromatography and by determination of the percentage which was unsoluble in 10% trichloroacetic acid, a proteolytic degradation could be made proof on the conditions of the plastein reaction. On addition of DL-methionine ethylesters to the partial hydrolysate an increasing incorporation of methionine into the plastein could be observed with increasing hydrolysis degree.     

The effects of the organic acids in cocoa on the flavour of chocolate

Samples (54) of dried fermented cocoa beans from different world regions were analysed for levels of organic acids, pH and titratable acidity. The effects of the organic acids on the flavour characteristics of cocoa were examined by sensory evaluation of chocolate made from samples of cocoa beans. Concentrations (g kg^?1) of acids ranged from 1.3 to 11.8 for acetic, 1-6 to 9-9 for citric, 0.6 to 11.1 for lactic and 2.1 to 6.5 for oxalic. pH values ranged from 4.6 to 5.8, while titratable acidity ranged from 0.08 to 0.31 equivalents of sodium hydroxide per kg sample. Cocoas from South East Asia and the South Pacific tended to be more acidic than West African beans in terms of both chemical and sensory characteristics. Lactic and acetic acids were found to be in greater concentrations in cocoas from the former regions and were considered to be largely responsible for higher acid flavour scores. In contrast, citric and oxalic acids were generally lower in these beans. Flavour assessments of cocoas with and without added organic acids indicated that oxalic acid played an important role in chocolate flavour. These results suggest that a reduction in the levels of acetic and lactic acids only, may not be sufficient to produce a desirable flavour balance.     

Formation of bitter peptides in cheese and from casein]

Whereas a slightly bitter taste is desirable in certain foods, it is an off-flavour in cheese which may even lead to unfitness for consumption. Bitter principles from cheese have been found to be peptides with molecular weights ranging from 2000 to 3000. For the purpose of further characterization, bitter peptides were isolated from enzymatic casein hydrolysates as well as from bitter cheese and purified. 30 proteases from different origins proved to be able to form peptides with bitter taste of varying intensity from casein. Present experience shows that the formation of bitter peptides during casein hydrolysis can be inhibited only to a very small measure. Bitter peptides are extrmely resistant to proteases, which is probably attributable to their high contents of hydrophobic amino acids and hydrophobic bonds. The detection of only N- or C-terminal amino acid in each of 11 different bitter peptides shows that peptide chains are present and not cyclic peptides as repeatedly assumed. It must be aimed at avoiding the cheese defect "bitter" by using appropriate starter cultures and rennet substitutes as little disposed as possible to produce bitter peptides.     

The cell count of milk in relation to milk yield

Quarter-milk cell counts and milk yields from 1000 cows in the province of Noord-Brabant were obtained over a 12-month period. The data from 933 animals, mainly heifers, were used to examine statistically the relationship between cell counts, as a criterion for sub-clinical forms of mastitis, and milk yield. Losses in milk were assessed by quarter, by pairs of quarters and by cow. The conclusions were that the losses in milk due to sub-clinical forms of mastitis, as indicated by cell count, can be substantial. The existence of a compensating increase in milk yield from a healthy gland, in response to the loss of milk from a neighbouring quarter with raised cell count, could not be demonstrated.     

The connective tissues of fish.

'Gaping' is a phenomenon in which the connective tissues of fish fillets fail to hold the blocks of muscle together. Slits appear across the surface of the muscle which cannot then be mechanically skinned, or, in the case of smoked salmon fillets, sliced.
Seasonal increases in the gaping of salmon fillets coincide with a fall in the postmortem pH of the flesh, occurring in June-July.
Extensive gaping can be caused by fish entering rigor mortis at too high a temperature. In trout, this temperature is considerably higher than in gadoids, suggesting that gaping from high-temperature rigor may in practice be fairly rare in salmonids.
The thermal denaturation temperature ( T _D) of acid-soluble collagen isolated from the turbot farmed in warmed water does not differ significantly from that of the connective tissues of those reared at normal temperatures. This observation is discussed in relation to gaping.     

Search for a more adequate test to predict the long-term migration from the PVC gaskets of metal lids into oily foods in glass jars

As shown previously, the conventional testing procedure for simulating long-term migration from the gaskets of metal closures into oily foods does not adequately reflect reality. It appears to be impossible to accelerate migration to the extent that the situation at the end of the shelf life of a product can be anticipated in a few days or weeks. Therefore, we investigated whether long-term migration could be extrapolated from migration rates determined for new lids. Jars were kept in the normal upright position. Since heat treatment may have a strong temporary impact, migration during the initial heating for pasteurization or sterilization and storage at ambient temperature were determined using different lids. Commercial products were recalled from sales points throughout Europe to determine the real migration over extended periods of time and for jars with differing histories. This migration was compared with data from the short-term testing to investigate whether an empirical relationship could be derived. The results show that the short-term test enables the comparison of lids and plasticizers in the initial phase of migration, but that long-term extrapolation presupposes more complex kinetic modeling. The results also demonstrate that the legal relevance of “official” testing methods should be reconsidered to avoid conflict when food contact materials comply with migration limits in the test but not in actual application.     

A LABORATORY STUDY ON COUNTERCURRENT DESALTING OF PICKLES

The technique of countercurrent leaching was applied to the desalting of salt stock pickles. Experiments and calculations showed that a spent brine of 13–14% salt can be produced in 4–6 stages and that pickles can be desalted in 48 hr. The volume of waste effluent from countercurrent leaching is considerably less than the amount from conventional leaching, and the higher concentration of salt in the effluent makes salt recovery much more practical from a cost standpoint.     

Protein hydrolysates from animal processing by-products as a source of bioactive molecules with interest in animal feeding: A review

Industrial processing of livestock, poultry and fish produces a large amount of waste in a solid or liquid form that can either be destroyed or be used to make compost, biogas or other low-added value products. However, the by-products from animal processing industries have a potential for conversion into useful products of higher value, such as protein hydrolysates, with interesting applications in animal feed. Low amounts of animal protein hydrolysates included in aqua-feeds may enhance growth rate and feed conversion of farmed fish and crustacean. Animal protein hydrolysates may also be incorporated in diets to enhance the nonspecific immunity of fish. As well, these hydrolysates can be used as a good source of amino acids for newly weaned animals. Protein hydrolysates from animal by-products including antimicrobials, antioxidants, opioid-like and/or other interesting bioactive molecules have promising and interesting applications on companion and production animals. By-products from animal processing industries are therefore a promising source of bioactive peptides of considerable interest for animal care, always within the framework of the existing legislation. Possible drawbacks and future trends of the use of animal by-products and/or production of protein hydrolysates from those materials are also discussed.     

Calculating Quantities of Ice for Cooling and Maintenance of Freshly Harvested Fish at Sea

Abstract: A new generalized model for predicting quantities of ice to cool and maintain freshly harvested fish at sea in insulated boxes is presented. The model addresses the universal need for fisherman to know in advance of going to sea just how much ice will be needed to cool down the expected day's catch to a desired temperature, maintain the catch, and to allow for losses. Illustrative predictions are presented for southern bluefin tuna (SBT) (Thunnus maccoyii) for a range of day's catch from 2000 to 8000 kg in ambient temperature ranging from 15 to 35 °C. The amount of ice needed to cool down SBT from an initial uniform harvest temperature of 28 °C to a maintenance temperature of 5 °C is shown to be the controlling contribution to total ice needed. Predictions highlight that a useful, safe rule‐of‐thumb is 1 kg of ice will be needed for each 3.5 kg of SBT. Importantly, the model is based on fundamental principles and predictive accuracy is demonstrated to be largely insensitive to a range of assumptions including volume of the void in the insulated boxes and overall coefficient of heat influx from ambient. The model can be used to predict the number of insulated boxes of defined dimension that will be needed to cool and hold the fish, ice and water for a wide range of fish species. It will be of interest to fisherman and boat owners and agents who invest in ice to preserve fish at sea. Practical Application: This research addresses the universal need for fisherman to know in advance of going to sea how much ice will be needed on‐board boats to cool down an expected day's catch to a desired temperature, maintain the catch and to allow for losses. The model is generalized and can be applied to a wide range of fish species.     

进口水产品及肉制品中沙门菌的检测分析

为保证进口食品安全，2004年2月～9月，对送检的262批进口水产品和45批进口肉制品进行增菌及分离培养。经miniVIDAS和API20E鉴定，确定3批水产品(2批印尼冻虾，一批印度冻黄姑鱼)、1批肉制品(产自美国的冻火鸡肉)沙门菌阳性。检出率分别为1．15％和1．22％。经血清学试验鉴定，冻虾中检出山夫登堡沙门菌(Salmonella senftenberg)，冻黄姑鱼中检出巴雷利沙门菌(Salmonella bareilly)，冻火鸡肉中检出蒙德维的亚沙门菌(Salmonella montevideo)。从上述产品中检出沙门菌，说明产品存在被沙门菌污染的可能，有可能引起肠道疾病。     

Computer optimization of distribution routes

The characteristics of a computerized system for delivery route planning are considered, and the information needed to develop the system and that to be expected from it are explained. Although route planning may be the original aim, strategic benefits almost always follow as a result of drawing conclusions about the performance of the delivery fleet. Cost savings generally arise from better route economy and from reduction in number and change in type of the delivery vehicles.     

Comparison of different laboratory methods for determining the formaldehyde emission from three-layer parquet floors

chamber method. The best correlation with the chamber method is achieved with the emission cells. The emission rates from different parts of a parquet sample (the front, the back and the edges) give different results. The formaldehyde emission from the back surface can be 20 times higher than from the front, so it is very important to do the test on the normally exposed surface. Also, the conditioning time effects the emission rate and should be maintained in a standardised way, so that results can be compared.