Anthocyanin Degradation in the Presence of Furfural and 5-Hydroxymethylfurfural

The influence of furfural (F) and 5-hydroxymethylfurfural (HMF) on degradation of cyanidin-3-glucoside (CG) was investigated in blackberry juice and in a citrate buffer model solution (pH 3,45) at 24°, 50° and 70°C. Presence of 0.012 M F or HMF accelerated pigment degradation. The acceleration was directly temperature-dependent, more pronounced in fruit juice, and considerably decreased in nitrogen. CG and HMF disappearance – but not the interaction between these compounds – followed the first-order reaction kinetics. The influence of formaldehyde (Fa) acetaldehyde (Aa) and benzaldehyde (Ba) on the stability of CG was investigated in blackberry juice. CG degradation effect of non-furane aldehydes (0.012 M) was Fa < Aa < Ba. CG and cyanidine (C) reactivities were studied by condensation with F and examination of molecular electrone properties (cyanidine, keto-pseudobase, anhydrobase, chalcone). Furfural did not react with CG but it did react with C. Electron charge distribution points to anhydrobase as the tautomeric form of C most reactive to F. Possible mechanisms of C decomposition in presence of F are proposed and discussed.     

Recognition of thin, flat microelectromechanical structures for automation of the assembly process

Visual recognition of microelectromechanical parts is necessary for automation of the assembly process. The visual recognition system that we have developed is based partly on neural networks and partly on digital image-processing techniques. The system takes grey-level microscope images and produces recognition code as the output as well as information about micropart position. The recognition procedure is not sensitive to micropart position. This is ensured by preprocessing based on calculation of the image moment properties. For the recognition, a supervised feedforward neural network is utilized. A combination of standard backpropagation and resilient propagation is chosen for learning the network. The performance of the system is tested on recognition of the parts of a microvalve system. The results are satisfactory with respect to recognition accuracy and recognition time.     

An heuristic strategy for multimodal search†

A heuristic search is described which has the aim of finding practically all extrema of a given non-linear functional. A standard unimodal descent algorithm is employed for finding individual extrema. This basic algorithm is applied repeatedly using various computed initial points and starting directions. Through an additional vise of several learning cycles most available extrema can be found. Numerical experiments indicate that the method is certainly very efficient for functionals of dimensions 15– 20 with 20–25 extrema.     

The formation of thermophilic spores during the manufacture of whole milk powder

A survey was undertaken at a whole milk powder manufacturing plant to determine the origin and the rate of spore formation of thermophilic bacteria. Spores were generally not detected (< 10 cfu/mL) in either the pasteurization process or the pasteurized milk directed into the powder plant. The predominant sites of spore formation were the preheater plate heat exchanger and the evaporator. Spores began to be detected approximately 9 h into an 18-h manufacturing run. Spore isolates were identified as Anoxybacillus flavithermus and Geobacillus species. A. flavithermus predominated in the preheat section, whereas a mix of both organisms was present in the later manufacturing stages.     

Influence of microencapsulation and transglutaminase on viability of probiotic strain Lactobacillus helveticus M92 and consistency of set yoghurt

The effect of microencapsulated probiotic Lactobacillus helveticus M92 cells and transglutaminase addition on the probiotic set yoghurt properties was investigated. Addition of probiotic bacteria, either free or microencapsulated in sodium caseinate, decreased the fermentation time and significantly enhanced the appearance and consistency of probiotic set yoghurt. Better survival of microencapsulated than free probiotic bacteria in produced yoghurts during storage, as well as during exposure to simulated gastrointestinal conditions, emphasises the efficiency of microencapsulation in the cell protection. Pretreatment of the milk with transglutaminase increased the gel strength and decreased the syneresis, which resulted in a better appearance and consistency of probiotic set yoghurts.