Contamination routes of Gram-negative spoilage bacteria in the production of pasteurised milk,evaluated by randomly amplified polymorphic DNA (RAPD)

The sources of contamination for Gram-negative psychrotrophic bacteria (GNP), have been traced in three dairies by using the PCR-based method randomly amplified polymorphic DNA (RAPD). GNP isolated from raw and pasteurised milk, air, water and empty packages were RAPD-typed. Pasteurised milk was found to be recontaminated by a wide spectrum of different RAPD-types. Several of the milk contaminating RAPD-types were also found in condensed water on the filling nozzles, in waste-water at the bottom of the filling machine, and in the air in the immediate surroundings of the machine. Most of the RAPD-typed bacteria were categorised as pseudomonads. The majority of these belonged to Pseudomonas fluorescens, but also Pseudomonas putida, Pseudomonas corrugata, and Janthinobacterium lividum were identified. Indications of specific RAPD-types associated with the same filling machine over a time period of 6–15 months were found in two of the dairies.     

Structural and physical properties of dietary fibres,and consequences of processing on human physiology

Dietary fibre encompasses very diverse macromolecules exhibiting a large variety of physico-chemical properties. They might be naturally present in the food (in cell walls of vegetables and fruits, for instance) or introduced in the food to improve their nutritional properties (e.g. bran in bread products) or their physical characteristics (e.g. gelling agents or improved resistance to storage). The properties that are nutritionally relevant are mainly the particle size and bulk volume, the surface area characteristics, the hydration and rheological properties, and the adsorption or entrapment of minerals and organic molecules. Amongst these properties, the viscosity and ion exchange capacity are the main contributors to metabolic effects (glucose and lipid metabolisms) whereas fermentation pattern, bulking effect and particle size are strongly involved in effects on colonic function. Technological treatments can modify the physico-chemical properties of the fibre. This can be further exploited to optimise both their techno-functional and physiological properties.     

Using object-oriented technology to design efficient IEEE-488.2 (GPIB) interface instruments

IEEE-488.2 interface (or popularly known as GPIB interface) -based instruments are very common in the test and measurement industry. The most important characteristics of the firmware for such instruments are small code size and ease of implementation and maintenance. Object-oriented (OO) techniques can be used to exploit their inherent advantages and the paper demonstrates the design of firmware for an IEEE-488.2-based instrument using OO techniques. The advantages of encapsulation allow for ease of comprehension besides ease of implementation and maintenance. This design was used to implement the firmware in a high-end test and measuring instrument and the advantages that ensued are discussed. As a consequence, an inadequacy in the IEEE-488.2 standard was detected which is also pointed out in the paper.     

Content of amino acids and the quality of protein in Brussels sprouts,both raw and prepared for consumption

The aim of the investigation was to evaluate the content of amino acids and the quality of protein in Brussels sprouts. The investigation included the raw material, cooked sample and two types of frozen product stored at ?20 °C for 12 months and then prepared for consumption. The frozen products investigated were obtained using the traditional method (blanching before freezing) and the modified method (cooking before freezing, then defrosting and heating in microwave oven after refrigerated storage) of the ready-to-eat type. Brussels sprouts, both fresh and prepared for consumption, were a good source of protein and amino acids. Proline and glutamic acid were dominating; leucine and tyrosine with phenylalanine were limiting amino acids. The product obtained by modified method contained 16% less amino acids in 16 g N than the raw material and 14% less than the raw material after cooking, and also 10% lower than that of the traditionally obtained product.     

Identification of empirical transfer function coefficients for a hollow tile based on detailed models of coupled heat transfers

Numerical simulation of transient heat transfer through a hollow tile, two air cells deep, is carried out using the SIMPLE algorithm. The coupling between the heat transfers by conduction, convection and radiation is taken into account. The heat fluxes computed for realistic time-varying excitations are used to derive empirical transfer function coefficients using an identification technique. Dynamic responses of the hollow tile predicted using both the transfer function coefficients and the simulation program are compared for thermal excitations that differ from those used to derive the coefficients. The results show a very good agreement between the two procedures’ predictions.     

The wine proteins

Proteins are typically present in wines in low concentrations, contributing little to their nutritive value. However, they assume a considerable technological and economical importance because they greatly affect the clarity and stability of wines. Although exhibiting a large diversity, the majority of the wine proteins are structurally related and have been identified as pathogenesis related (PR) proteins. Thus, different wines are essentially composed by identical sets of polypeptides. They derive from the grape pulp, and survive the vinification process simply because they are highly resistant to proteolysis and to the low pH characteristic of wines. There is increasing evidence suggesting that although protein-dependent, the development of turbidity in wines is controlled by a number of factors of non-protein origin, such as polyphenols, the wine pH and the presence of polysaccharides. A variety of procedures has been developed and tested for the specific removal of proteins from wines. Even though bentonite fining is nonspecific and can impair the quality of wine, it remains the only effective method to stabilize wines.     

Instrumental and sensory analysis of Greek wines; implementation of principal component analysis (PCA) for classification according to geographical origin

Wine is one of the most important products of Greece and other Mediterranean countries. Adulteration of wines, either in terms of geographical origin or variety, has been a major topic of debate and extensive research. Various instrumental methods (gas chromatography, high pressure liquid chromatography) and sensory analysis, in conjunction with statistical analysis, were developed and applied in an attempt to provide reliable answers to this issue. This research aimed at classifying 33 greek wines from various regions by employing both instrumental and sensory analysis. Application of principal component analysis (PCA) to our experimental data resulted in satisfactory classifications of only Greek red wines in terms of their geographical origin. Greek wines were effectively distinguished in two or three groups (depending on PCA figure); wines from Aegean/Ionean islands. North Greece and South Greece. However, further work with greater numbers of samples is required in order to draw more valid conclusions and to obtain a detailed map of greek wines according to their geographical origin and variety.     

Characterizing the astringency of red wine: a case study

Red table wines of quality are characterized by pleasing and complex mouth-feel sensations, the most important of these being astringency. While a comprehensive set of terms has been developed over time to describe the flavor of red wines, an appropriate vocabulary describing the astringent sensations produced by these wines is not well defined. This paper presents a structured vocabulary derived by a panel of experienced wine tasters that can be used to describe the astringent sub-qualities of red wines. Multidimensional scaling of sorting data showed that an experienced panel and a group of skilled red wine-makers had similar interpretations of the relationships among the astringency terms. A tasting panel was successfully trained to identify and consistently rate the intensity of the astringent sub-qualities encountered in a set of one year old Shiraz wines. A novel approach of using finger touch standards to represent the astringent sensations experienced in the mouth was utilized.     

Diversity in nutritional composition of wild jack bean (Canavalia ensiformis L. DC) seeds collected from south India

Nine accessions of the wild jack bean (Canavalia ensiformis L. DC) seeds collected from nine different locations of south India were analysed for proximate composition and mineral profiles. The major findings of the study were as follows: crude protein ranged from 28.9 to 35.0%, crude lipid 3.4–4.7%, crude fibre 7.0–10.7%, ash 3.0–5.8%, carbohydrates 46.1–54.5% and energy levels 1469–1574 kJ 100 g⁻¹ DM. Significant (P<0.05) diversity was observed in crude protein and carbohydrate contents among the accessions collected from different locations based on analysis of variance (ANOVA) analysis. Potassium was the most abundant mineral, which ranged from 634 mg 100 g⁻¹ in Dasukuppam accession to 1017 mg 100g⁻¹ in Valacode accession. Sodium and magnesium levels are generally low with mean values of 63 and 250 mg 100 g⁻¹, respectively. In the present study, in all minerals, significant diversity was observed among the accessions collected from different locations.     

Blending response surface methodology and principal components analysis to match a target product

Highly trained sensory panels have long been used to evaluate food products on perhaps dozens of attributes. Principal components analysis is one of a number of multivariate data analysis techniques commonly used in analyzing sensory panel data. More recently, response surface designs have been used to direct the creation of product prototypes so that the effects of ingredient levels and/or processing conditions can be modeled. This paper will discuss how the two methodologies have been used together in projects where the goal is to identify ingredient levels and/or processing conditions that best match a target product's sensory profile. Some unique problems arise when analyzing and interpreting the results of response surface models when the number of responses is quite large. This paper will explain how some of these problems have been addressed through the detailed discussion of the development of a cost reduced product. Six ingredients were systematically varied in a response surface design to create 48 prototypes. The prototypes and the target product were then measured on 33 sensory attributes. Design selection, data collection, response surface modeling, rotated principal components analysis and the use of both desirability and distance functions to identify ingredient level combinations that meet the product development objectives will be discussed in detail using the data analyses from this project. Recommendations for next steps in the product development process will also be given.