Kalman-Bucy filtering for stochastic Volterra models

In this paper a suboptimization procedure is formulated for Volterra-type equations by using the Kalman-Bucy filtering theory. The Volterra-type systems are, in general, of a time-varying and non-convolution nature, but we include the time-invariant and convolution cases     

Phytoplankton pigment patterns in the Canary Islands area as determined using Coastal Zone Colour Scanner data

Abstract

Data from the Nimbus-7 Coastal Zone Colour Scanner (CZCS) were analyzed to determine the phytoplankton pigment patterns in the ocean surrounding the Canary Islands. Two different pattterns were observed in this region. One pattern was associated with the influence of the northwest African coastal upwelling system on the ocean surrounding the Canary Islands and the other was associated with individual islands, probably due to the disruptive effect of the Canary Islands on the flow of the Canary Current     

Colour and texture changes during sterilization of packed ripe olives

There were no temperature- or time-dependent significant changes in colour or iron content of two cultivars of bottled ripe olives during heat sterilization at temperatures between 117 and 129°C. the addition of calcium had no effect on the activation parameters of texture, although the olives were always firmer when the cation was added. the z-values for the texture of ripe olives were found to be around 20°C and the average activation energy was 138 kJ/mol.     

A HIGH PROTEIN PRODUCT FROM CHICKPEAS (Cicer arietinum L.) BY ULTRAFILTRATION. PREPARATION and FUNCTIONAL PROPERTIES

Using a flat plate ultrafiltration system, Direct Ultrafiltration (DU) and Discontinuous Diafiltration (DD) were used to produce a High Protein Product (HPP) from chickpeas ( Cicer arietinum L. ). the chickpea extract (3.3% total solids) was concentrated up to 65% of protein by DD mode. Chickpea flour and spray-dried HPP were analyzed for proximate analysis and functional properties having a Commercial Soybean Isolate (SBI) as a control. the average water absorption found for the HPP (97.4%) was relatively low compared to the raw material, chickpea flour (121.2%) and SBI (115.2%). HPP had a higher fat absorption (52.2%) than flour (39.6%) and SBI (34.0%). Foam capacity and stability of the HPP were similar to those of the SBI and both were more stable than the flour. the HPP, SBI and flour had their lower nitrogen solubility within the pH range of 4–6. Recovery of 72.8% total nitrogen and removal of 59.3% Nonprotein Nitrogen (NPN), from chickpea extracts, were achieved by this system.     

Physical, Chemical, Nutritional and Sensory Properties of Corn-Based Fortified Food Products

Product formulations and processing methods were developed using seven corn-based flours. They were fortified with various levels of sesame, chickpea, soybeans, powdered egg, nonfat dry milk, lysine, and methionine. Products were formulated to provide as closely as possible the FAO requirements for essential amino acids and to have acceptable physical, chemical, nutritional, sensory properties and cost. The overall nutritional value was increased at least by 92% as compared to similar existing products. There were no obvious differences in physical properties of the fortified flours and products as compared to commercial counterparts. The protein cost of the fortified products was less than that of food from animal sources; the PER values being the same or higher.     

FLAVOR AND CHEMICAL COMPARISON OF PASTEURIZED AND FRESH VALENCIA ORANGE JUICES1

Freshly extracted Florida Valencia orange juice was heated at 98C for 11 s to produce lightly heated juice, and for 37 s to produce heavily heated juice. Sensory panels detected a flavor difference between the fresh, unheated juice and the heavily heated juice. Analyses of these two juice samples by headspace gas chromatography (GC) showed no significant qualitative or quantitative differences. GC analyses of methylene chloride extracts of juices and of residues from distillation of the juices showed only one detectable difference in each case. Extracts of the whole juices showed one GC peak, which was significantly larger in the heavily heated juice, identified as the potential off flavor compound, octanoic acid. Extracts of the high-boiling distillation residue showed one unidentifed late-eluting GC peak which appeared only in the heavily heated juice. These findings supplement previous reports that more severe pasteurization conditions than required for juice processing cause detectable flavor changes in heated juice.     

EFFECT OF SETTING CONDITIONS USING MICROBIAL TRANSGLUTAMINASE DURING OBTENTION OF BEEF GELS

Microbial transglutaminase (MTG) is a food additive widely used to improve the mechanical properties of beef, poultry and fish gels. The aim of this study was to determine the effect of incubation temperature on the mechanical properties of restructured beef gels treated with MTG. The restructured beef gels were obtained by adding 0.0% (untreated) or 0.3% MTG. Three incubation temperatures (40, 50 or 60C) for 30 min were used, followed by cooking at 90C for 15 min. Control samples without incubation were also prepared. Changes in the mechanical properties (texture profile analysis and puncture test), color attributes, expressible water and cooking loss were determined. Results indicated that the maximum mechanical properties can be obtained by incubating beef pastes at 50C for 30 min with minimal effect on color, expressible water and cooking loss when 0.3% of MTG is added.

PRACTICAL APPLICATIONS

Meat and poultry are considered nonsetting proteins, and consequently, an incubating treatment to allow optimal cross-linking has not been considered, and the products are usually obtained by direct cooking. Our results showed that beef gels containing 0.3% of microbial transglutaminase incubated at 50C showed higher mechanical properties than control gels without incubation. These results could be useful to improve the mechanical properties of beef gels.     

CHANGES IN VOLATILE FLAVOR CONSTITUENTS IN PASTEURIZED ORANGE JUICE DURING STORAGE1

Pasteurized orange juice which was packaged in laminated gable top cartons was stored for the expected shelf‐life of 9 weeks at 2C and at ?18C (control sample). Periodic quantitative analysis of 46 volatile constituents by headspace gas chromatography (HSGC) showed a gradual decrease during the first 4 weeks and a more rapid drop after 5–6 weeks of storage. The decrease was greater for water soluble than for oil soluble constituents. HSGC of the laminated composite carton revealed an initial rapid absorption of many volatile constituents. A sensory panel found a significant decrease in the hedonic rating of juice stored for 7 weeks at 2C compared with that for the starting juice. Triangle difference and paired preference tests showed no differences between juices stored at 2C and those stored at ?18C for the same length of time, and no preference for either juice stored at 7 or 9 weeks for the same length of time.