ASPECTS OF NITROSATION IN MALTS AND BEERS. I. EXAMINATION OF MALTS FOR THE PRESENCE OF N-NITROSOPROLINE,N-NITROSOSARCOSINE AND N-NITROSOPIPECOLINIC ACID

By extraction of acidified aqueous extracts of malt with organic solvents, methylation of the resulting extracts, gas chromatography and detection with a nitrosamine-specific detector, it is shown that N-nitrosoproline is present in malt and that N-nitrososarcosine is sometimes present. N-Nitrosopipecolinic acid has not been observed.     

冰泥在食品储藏与保鲜中的应用

为了加快冰泥制冷系统在食品储藏和保鲜中的应用,介绍了冰泥的性质,着重讨论了冰泥在鱼类储藏、奶食品加工、零售食品商场内的应用以及其他场合下的应用.在鱼类储藏中,对冰泥和冰片两种不同储存方式下的储藏效果进行了比较,得出在冰泥中储藏的鱼能够保持较好生物性能和较高保鲜度.列举了冰泥在奶食品加工和零售食品商场中应用的例子,分析了冰泥能够节能的优良性质,并简单介绍了在其他果蔬和肉食品中的应用.     

RADIOASSAY OF FOLACIN IN FOODSTUFFS

A commercial radioassay kit for folate (Radio-chemical Centre Amersham, England), produced for clinical analysis, has been tested for folacin assay in foodstuffs. The binding capacity of porcine binder was determined for different folates and compounds interfering with the microbiological assay. Recovery of standard addition of N⁵-methyltetrahydrofolate to the foodstuffs extracts estimated by radioassay varied from 96 to 105%.     

MEASUREMENT OF CESIUM-137 IN FOODSTUFFS

Intensity of the 662‐keV gamma ray from cesium‐137 was closely monitored in a variety of foods and beverages, including milk, flavored milk, fruit juices, infant foods, cooking oil, biscuits and fish. Nuclear facilities in the region, and the proximity of Oman to India and Pakistan (where nuclear material exists) played an important role in influencing our investigation. Relevant food items were obtained at appropriate intervals from January to December 2003 and 2004, and subjected to high‐resolution gamma‐ray measurement with a 28‐cm² high‐purity germanium detector. Each sample was prepared in a suitable Marinelli beaker and counted for 12 h. The recorded specific activities in milk, fruit juices and oil were generally <1.0 Bq/L, and <2.0 Bq/kg in solid foods such as fish and biscuits. In general, we found that the food quality in this respect was high.     

高温加热食品丙烯酰胺问题的探讨

丙烯酰胺对人和动物是一种有效累积性神经毒物，近年来研究发现在高温加热食品中有丙烯酰胺产生，本文介绍了高温加热食品中丙烯酰胺的形成机理、影响其形成的各种因素以及测定其含量的各种方法，最后提出了降低丙烯酰胺的一些措施．     

PROCESSING TECHNIQUES AND HYDROCYANIC ACID CONTENT OF CASSAVA-BASED HUMAN FOODSTUFFS IN NIGERIA

The hydrocyanic acid content of peeled cassava tubers from various localities in Eastern Nigeria (major cassava growing and consuming area) varied from 26 ± 1.6 to 38 ± 2.6 mg/100g fresh weight. There was no correlation between the cyanide contents of cassava tubers and locality. Processing the tubers with the highest cyanide content into different forms of cassava-based foodstuffs (i.e. Garri, Fufu, cassava cake and cassava chips for cassava salad) consumed in Nigeria resulted in an undetectable amount of cyanide. It is concluded that these cassava-based foodstuffs consumed in Nigeria are free from cyanide toxication, and the incidence of ataxic neuropathy associated with prolonged consumption of cassava as a result of its cyanide content should not be due to prolonged consumption of processed cassava products.     

LIQUID FOODSTUFFS EXHIBITING YIELD STRESS AND SHEAR-DEGRADABILITY

Two rheological properties of liquid foodstuffs often encountered in practice are the yield stress and the shear-degradability (irreversible time-dependence). Both these properties were determined for meat and yeast extracts using two rotational viscometers. The material constants were obtained and fitted with Bingham Plastic and Herschel-Bulkley models for the meat extracts. The shear-degradability exhibited by the yeast extract was quantified in terms of the energy required to destroy the material structure.     

PREVALENCE OF LISTERIA MONOCYTOGENES IN SOME TURKISH FOODSTUFFS

In this study, the presence of Listeria monocytogenes was evaluated in basic groups of foods in Ankara, Turkey between 2001 and 2002. Eighty prepared ground meat, 100 white cheese and 100 parsley samples were obtained from different markets where they were offered for consumption. L. monocytogenes was detected according to the method of ISO Draft International Standard. Fraser Broth was used for enrichment process, and isolation of Listeria spp. was carried out by Oxford Agar. L. monocytogenes was then identified by biochemical and serological tests. L. monocytogenes was isolated from 13.75, 4 and 2% of 80 prepared ground beef, 100 white cheese and 100 parsley samples, respectively. The results indicate that these foodstuffs have risk of L. monocytogenes. Contamination of L. monocytogenes was not detected in packaged ground beef and white cheese samples. High incidence rate of L. monocytogenes was noted for the samples from open and local market.     

流动注射分光光度法测定食品中的微量硼

基于硼和3-甲氧基-甲亚胺H在HAC-NH4AC缓冲溶液中的显色反应,建立了流动注射光度分析测定微量硼的新方法.在28样/h采样频率下检出限为0.033 mg/L,硼浓度在0.033 mg/L～5 mg/L范围内符合比耳定律,相对标准偏差为0.54%.该法快速,简便、灵敏、试剂用量少、选择性好,用于食品中微量硼的测定,结果令人满意.     

STRUCTURAL AND CHEMICAL BASES FOR TEXTURE OF PLANT FOODSTUFFS

Following a brief review of plant morphology, tissue organization and cell structure, the structure/texture relationship in edible plant materials is discussed with special emphasis on the role of cell wall and cytoplasmic components (starch, protein, lipids and vacuolar solutes). The review of published experimental data is supplemented with information deducible from interfacing the disciplines of plant physiology/microscopy and food science/texture. Recent engineering studies on tissue failure are discussed and their relevance to the advancement of the structure/texture relationship is pointed out.     

流动注射分光光度法在食品分析中的应用

对近年来流动注射分光光度法技术在食品分析领域取得的进展进行了综述,介绍了流动注射分光光度法测定食品中微量元素、蛋白质及氨基酸、维生素、食品添加剂等的应用.     

RHEOLOGICAL AND SENSORY PROPERTIES OF POPULAR GREEK FOODSTUFFS: A REVIEW

The rheological and sensory properties that constitute the quality benchmark of Greek foodstuffs are identified in a critical fashion and prevailing practices are discussed in relation to home-made and industrial production. Formulation modifications aimed at enhancing the appeal of products in terms of organoleptic characteristics and nutritional impact are also presented. Olive oil occupies an important position in the Greek diet and it is characterised by a unique flavour. Accurate determination of flavour is carried out using the sensory wheel, which unveils the grade of the product. Among foods with soft-solid characteristics, traditional Feta cheese has a prominent place and it is well known for a salty, slightly acidic taste. Ageing within a year results in textural changes from a soft and elastic consistency to a hard and brittle body. Full and low fat Greek yoghurts are consumed widely locally and abroad. The mouthfeel of the product changes from that of a week gel to a viscous fluid at a fat content of 10% and 2%, respectively. Finally, emulsion-type products range from commercial salamis to traditional sausages, which satisfy culinary requirements for a ‘rubbery' or ‘spreadable' texture depending on the favourite pastime dinner. It is hoped that the treatise will unveil the appetising features of Greek foodstuffs, which are increasingly recognised by the international consumer.