感官评价及其在谷物制品中的应用现状

简要介绍了感官评价的定义、应用及其在食品工业中的重要性。重点阐述了感官评价在部分谷物制品评价中的应用,包括大米食味和小麦粉制品食用品质的感官评价。详细描述了大米、面条、面包、馒头品质的感官评价方法、相关研究及存在的问题等。     

杂粮复合豆沙营养及功能品质评价

以薏米、苦荞分别与红小豆、红芸豆制成杂粮复合豆沙,检测其蛋白质、氨基酸、淀粉等宏量营养素以及黄酮、多酚、花青素等微量活性成分含量,并对营养品质及功能成分进行综合评价。结果表明,与红小豆沙和红芸豆沙相比,薏米或苦荞复合豆沙的蛋白质、总淀粉、慢消化淀粉、抗性淀粉、氨基酸总量、必需氨基酸、黄酮、多酚、花青素等营养功能成分含量均显著增加(P0.05)。基于主要营养、功能物质含量,采用主成分分析(PCA),7个豆沙样品营养价值由高到低依次为:苦荞红小豆沙薏米红小豆沙苦荞红芸豆沙薏米红芸豆沙红小豆沙红小豆沙(市售)红芸豆沙,这表明杂粮复合豆沙具有更高的营养功能品质。     

Mycotoxins in cereal grain Part VOL Microbiological evaluation of cereal grain quality,connected with mycotoxins occurrence

Four classes of microbiological quality of cereal grain are proposed. For classification the frequency of kernels contamination with Penicillia, Aspergilli and Phycomycetes is considered as essential. Lots contaminated with mycotoxins (ochratoxins) were usually of IIIrd and IVth class of quality.     

真空包装在谷、豆类食品中的应用

<正> 大型购物中心和超级市场的迅速崛起,使传统的食品包装形式出现了许多问题,不得不从根本上进行改变。一般来说,大型分销中心要求的产品体积较大,而且同类的产品会被并排放置于货架上,从而带来激     

Physical evaluation of popped cereal snacks with spent hen meat

Various blends of spent hen meat and grains (potato starch, corn starch, and rice flour) were popped using a popping machine. Lowest bulk density was observed in the snack with 1:2 ratio of meat and potato starch. Except for the popped snack with meat and rice flour, as the starch content increased, bulk density decreased gradually. Popped snacks with grains only were higher in L* value than those with meat and grains. The a* and b* values increased with increasing meat content. All popped snacks were significantly different (P<0.001) in bulk density, color, and breaking force. As the grain content of snacks increased, the size of the air cells also increased. Results of scanning electron microscopic and optical microscopic observations revealed the popping degree of snack with starch and spent hen meat was affected by the presence of meat. The optimum ratios of meat to grain for high expansion ratio were determined to be 1:2 and 1:3 of meat to corn starch and potato starch.     

焙烤类谷物食品糖基化产物的定性、定量评价方法

糖基化产物与心血管疾病、糖尿病等多种慢性病的发生有关,因此对食品中糖基化产物含量的评价尤为重要。研究了不同酶解条件对结合态糖基化产物的释放,并且建立了以色度、吸光度、荧光强度等为考察指标综合评价不同反应途径的糖基化产物含量的体系。结果表明:分别采用E320μg/mL和640μg/mL酶解焙烤类谷类食物,40℃酶解36 h,结合态糖基化产物释放较为充分。谷物早餐中美拉德反应产物含量低于饼干和面包;荧光性晚期糖基化终产物含量大小依次为:饼干(1 890 AU/mg)面包(1 886 AU/mg)谷物早餐(1 678 AU/mg)。另外,早餐谷物中初期(A_(208))、中期糖基化产物(A_(360))显著高于饼干和面包(P0.05),而早餐谷物中期和末期糖基化反应产物(戊糖素、5-HMF和HMF)含量显著低于面包和饼干(P0.05)。     

Research Watch: New measurements of mercury kinetics

Measurements.     

Hydration of casein micelles: kinetics and isotherms of water sorption of micellar casein isolated from fresh and heat-treated milk.

Water vapour sorption isotherms of casein micelles prepared from raw milk and various heat-treated milks were determined. The equilibrium water contents of the heated preparations were markedly lower than that of the raw-milk casein over the whole range of vapour pressures studied. An analysis of the sorption isotherms in the relative vapour pressure range 0.1--0.45, according to the Brunauer, Emmett & Teller (1938) equation, showed that there were significant differences between preparations in the computed monolayer contents. Differences in the rates of water sorption were also observed between the different preparations. As judged from the amount of absorbed water, the influence of the heating methods could be ranked in the order: HTST (92 degrees C) approximately UHT (direct) less than UHT (indirect) less than HTST (72 degrees C).     

Effect of maturity on degradation kinetics of sod-seeded cereal grain forage grown in northern Arkansas

Wheat (Triticum aestivum L.), oat (Avena sativa L.), and rye (Secale cereale L.) were overseeded into a dormant bermudagrass (Cynodon dactylon (L.) Pers.) sod and harvested at 3-wk intervals throughout March, April, May, and early June. Plant growth stage was documented for each forage on each harvest date, and harvested forages were evaluated for forage quality characteristics. Degradation kinetics of DM and NDF for these forages were evaluated by the in situ method. Fractional degradation rates for DM and NDF in all three species were relatively rapid for vegetative forage (> or =0.086 h(-1)) but declined rapidly by the heading stage of development and stabilized thereafter. Forage quality declined and forages were more resistant to ruminal degradation as plants entered the reproductive stages of growth. Based on these findings, growth stage is an effective predictor of most characteristics of in situ DM and NDF disappearance. The relationships between these degradation parameters and growth stage were typically explained with quadratic or cubic models. Clearly, forage quality characteristics of overseeded rye deteriorated more rapidly with phenological development and growth stage than quality characteristics of overseeded wheat and oat grown in the same environment. For rye, this problem is further complicated by its accelerated phenological development. These factors combine to permit a very narrow harvest window in early spring, relative to the other cereal grains evaluated. Acceptable forage quality may persist for an extended period in wheat and oat; this suggests that producers wishing to utilize these forages may lengthen the harvest window by planting more than one species, either as a mixture or preferably in independent stands.     

Nutritive value of middle eastern foodstuffs. II. Composition of pulses, seeds, nuts and cereal products of Lebanon

Values were determined for proximate composition and for the energy, calcium, phosphorus, iron, thiamine, riboflavin and niacin content of locally available varieties of pulses, seeds, nuts, grains and grain products. The importance of these foods in the Lebanese diet is discussed.     

Effect of milk fat and total solids concentration on the kinetics of moisture uptake by ready-to-eat breakfast cereal

Summary When immersed in milk, breakfast cereal easily take up moisture, lose their brittle texture and become soggy. Earlier comparative analysis of the moisture sorption by breakfast cereal immersed in water and milk indicated that milk solids might play an important role on the sorption kinetics. In this work, the moisture uptake by ready-to-eat corn breakfast cereal immersed in milk solutions, reconstituted from whole and skimmed milk powder, was measured under isothermal conditions at 5, 30 and 55 °C. Dilutions between 0.25 and 1.5 were tested, with the factor of dilution 1 corresponding to the standard recommended by the milk powder manufacturer. The Weibull probabilistic model adequately fitted the experimental data by appropriate choice of its variable parameters. The dependence of the model parameters on temperature and total solids concentration was assessed for both skimmed and whole milk. Fat was found to play a major role on the process mechanism, which was attributed to the deposition of a fat layer at the solid matrix surface, hindering water and solids uptake. Yet, for short times, moisture uptake proceeded at a similar rate both in skimmed and whole milk.     

Investigations on the evaluation of rheological properties of cereal based viscoelastic fluids using ultrasound

The ultrasonic approach provides a non-destructive, rapid and low cost technique for the measurement of physical characteristics of dough. The traditional approaches for dough testing are slow and off line and do not provide fundamental rheological information in the production line nor while processing. The baking industry is in need for such a tool to achieve final product quality and consistency.     

Mycotoxins in cereal grain Part VII. A simple method to assay mycotoxin potential of cereal grain and cereal products

A simple test to assay mycotoxin potential of cereal grain and products was elaborated. In cereal grain samples during 1977 and 1981 formation of ochratoxin A, citrinin and zearalenone was observed respectively in 40%, 7 % and 31 % of cereals samples. Aflatoxin and sterigmatocystin were not formed in any sample of cereal grain. Citrinin and penicillic acid were found as mycotoxins accompanying ochratoxin A.     

Comparative evaluation of edible coatings to reduce fat uptake in a deep-fried cereal product

Eleven hydrocolloid materials including gelatine, gellan gum, κ-carrageenan-konjac-blend, locust bean gum, methyl cellulose (MC), microcrystalline cellulose, pectin (three types), sodium caseinate, soy protein isolate (SPI), vital wheat gluten and whey protein isolate (WPI) were compared for their film forming ability, suitability for fried foods, and water and fat transfer properties. Various selected formulations and preparation methods were investigated for their effectiveness, and for their heat stability on a product made from a pastry-mix. Gelatine, wheat gluten and sodium caseinate were not suitable in single material coating. The SPI, WPI and MC were the best materials for coating to reduce fat uptake during frying. Composite films of two to three materials in multiple coatings or a single coating with mixed materials were also evaluated. Multiple coatings provided large film thicknesses. SPI/MC and SPI/WPI mixed coatings provided the highest index value (reduction in fat uptake/decrease of water loss), and reduced the fat uptake up to 99.8%.     

Mycotoxins in cereal grain. Part VII. A simple method to assay mycotoxin potential of cereal grain and cereal products

A simple test to assay mycotoxin potential of cereal grain and products was elaborated. In cereal grain samples during 1977 and 1981 formation of ochratoxin A, citrinin and zearalenone was observed respectively in 40%, 7% and 31% of cereals samples. Aflatoxin and sterigmatocystin were not formed in any sample of cereal grain. Citrinin and penicillic acid were found as mycotoxins accompanying ochratoxin A.     

SOA formation by biogenic and carbonyl compounds: data evaluation and application

The organic fraction of atmospheric aerosols affects the physical and chemical properties of the particles and their role in the climate system. Current models greatly underpredict secondary organic aerosol (SOA) mass. Based on a compilation of literature studies that address SOA formation, we discuss different parameters that affect the SOA formation efficiency of biogenic compounds (alpha-pinene, isoprene) and aliphatic aldehydes (glyoxal, hexanal, octanal, hexadienal). Applying a simple model, we find that the estimated SOA mass after one week of aerosol processing under typical atmospheric conditions is increased by a few microg m(-3) (low NO(x) conditions). Acid-catalyzed reactions can create > 50% more SOA mass than processes under neutral conditions; however, other parameters such as the concentration ratio of organics/NO(x), relative humidity, and absorbing mass are more significant. The assumption of irreversible SOA formation not limited by equilibrium in the particle phase or by depletion of the precursor leads to unrealistically high SOA masses for some of the assumptions we made (surface vs volume controlled processes).     

Direct evaluation of the total antioxidant capacity of raw and roasted pulses, nuts and seeds

Pulses, nuts and seeds represent an important part of human diet in many countries and epidemiological studies associated their consumption with many health benefits. These foods are often consumed after roasting that may destroy some bioactive compounds, but it can also form antioxidant compounds through the Maillard reaction. In this paper, a direct procedure for the extraction-independent measurement of the total antioxidant capacity named QUENCHER was applied to raw and roasted pulses, nuts and seeds. The results highlighted a high value of total antioxidant capacity (TAC) for some raw seed and pulses showing marked inter-varietal differences among beans examined. TAC value measured by QUENCHER was generally higher than that found using multiple extraction procedure. The effect of roasting on the TAC is the result of the thermal degradation of naturally occurring antioxidant compounds and the formation of new Maillard reaction products having antioxidant activity. In most of the foods studied, the final balance was negative with a substantial loss of antioxidant activity upon roasting. The main driver of the final TAC is the presence of reactants: in rich-starch materials, such as chickpea, cashew and borlotti beans, roasting is accompanied by a progressive increase in TAC, which is likely related with the formation of antioxidant Maillard reaction products.     

Inactivation kinetics of some microorganisms in apple,melon, orange and strawberry juices by high intensity light pulses

The suitability of some models was analyzed to characterize the Pulsed Light (PL) inactivation kinetics for Escherichia coli ATCC 35218, Listeria innocua ATCC 33090, Salmonella Enteritidis MA44 and Saccharomyces cerevisiae KE162 in commercial juices and fresh squeezed juices. A negative relationship was found between the absorbance of juices and PL effectiveness. PL treatment (2.4–71.6 J/cm²) was ineffective in natural strawberry and orange juices. In general, inactivation curves exhibited a marked upward concavity, reaching after 60 s-PL treatment to 0.3–6.9 log-reduction cycles. Nonlinear semilogarithmic survival curves were fitted by conceptually different models: the Weibull model, the biphasic model and a modified version of the Coroller model. Biphasic and Weibull models compared to the modified Coroller model allowed a better fit and more accurate estimation of parameters. A multivariate approach to data analysis by principal components (PCA) showed relevant spatial relationships among estimated model parameters, revealing PL treatment efficacy in the different juices.     

单侧假设检验和置信区间在钢丝绳破断拉力评价中的应用

介绍单侧假设检验和置信区间在钢丝绳破断拉力评价中的应用。从某段时间依据标准API 9A、JIS G3525和GB 8918生产的所有钢丝绳中,根据1个标准抽取1组子样的原则进行抽样并统计分析。根据统计分析的结果可得出结论:(1)单侧假设检验可以对批量钢丝绳破断拉力的质量水平进行分析;(2)区间估计可以给出批量钢丝绳破断拉力值的大致范围。