An NMR pulsed field gradient study of the electrical and conventional heating of carrot

Experiments have been carried out using pulsed field gradient NMR to characterize the self-diffusion of water within samples of carrot, both uncooked and cooked by either volumetric electrical or conventional heating. The method detected the presence of structure within uncooked carrot, and the disappearance of the structure on cooking. The NMR data were fitted to two models: (i) an analytical solution for diffusion between impermeable barriers and (ii) a numerical solution to the more physically realistic situation of diffusion between permeable barriers. The barrier spacings obtained with raw carrot data using both methods (i) and (ii) were consistent with cell sizes found in carrots. The effect of cooking on the model fit was either an increase in barrier spacing (method i), or an increase in barrier permeability (method ii). There was a statistically significant difference between samples cooked electrically and conventionally, but this was much less than the difference between cooked and uncooked material.     

DEVELOPMENT OF A BLENDED NONALCOHOLIC BEVERAGE COMPOSED OF COCONUT WATER AND CASHEW APPLE JUICE CONTAINING CAFFEINE

ABSTRACT

In this work, the stability of a blended beverage composed by coconut water and clarified cashew apple juice (“cajuina”) is presented. The physicochemical, microbiological and sensory stability of a blended nonalcoholic beverage composed of coconut water and cajuina (80:20 v/v) were evaluated during 6 months. The results showed that the beverage presented good stability in all analyzed parameters except for vitamin C, which presented a loss of about 80% of the initial content. The beverage color also presented changes during the storage time. Despite these alterations, the product acceptance during the storage period did not show any rejection.

PRACTICAL APPLICATIONS

The development of blended beverages is a good way of improving the nutritional quality of traditional products. By mixing two or more kinds of fruits, a product with more vitamins and minerals and with different sensory and flavor characteristics when compared to the raw materials is obtained. In the present work, coconut water and cashew apple juice were mixed to obtain a different product combining the nutritional components from both fruits. The blended beverage combines the high vitamin C content of the cashew apple juice with the high mineral level of the coconut water. Caffeine was also added conferring stimulating properties to the product. The product acceptance was evaluated by sensory analysis and presented good acceptance until 6 months of storage at room temperature, presenting the required characteristics for a commercial product.

     

On improved crack tip plastic zone estimates based on T‐stress and on complete stress fields

Cracked ductile structures yield locally to form a plastic zone (pz) around their crack tips, which size and shape controls their structural behaviour. Classical pz estimates are based solely on stress intensity factors (SIF), but their precision is limited to very low σ_n/S_Y nominal stress to yield strength ratios. T‐stresses are frequently used to correct SIF‐based pz estimates, but both SIF and SIF plus T‐stress pz estimates are based on truncated linear elastic (LE) stress fields that do not satisfy boundary conditions. Using Griffith's plate complete LE stress field to avoid such truncated pz estimates, the influence of its Williams’ series terms on pz estimation is evaluated, showing that T‐stress improvements are limited to medium σ_n/S_Y values. Then, corrections are proposed to introduce equilibrium requirements into LE pz estimates. Finally, these improved estimates are compared with pz calculated numerically by an elastic–plastic finite element analysis.     

STORAGE STABILITY OF A STIMULANT COCONUT WATER-CASHEW APPLE JUICE BEVERAGE

Besides flavor, appearance and overall impression, food consumers seek foods rich in nutrients. Fruits are a rich source of nutrients and minerals, and fruit juices are a popular way of consuming them. Development of new products, where two or more kinds of fruit juices are blended to obtain a product that combines the nutritional value of both fruits, which present a different and pleasant taste, has been encouraged by the food industry and has been well accepted by consumers. In this work, the storage stability of a coconut water‐cashew apple juice (87.5:12.5 v/v) beverage was evaluated. Caffeine addition (100 mg/L) conferred stimulating properties to the blend. The physicochemical, microbiological and sensory stability of this blended beverage was evaluated during 6 months. The results showed that the beverage presented good stability for all parameters that were analyzed except for vitamin C, which presented a loss of 58% from the initial content.     

Multivariate statistical approaches for wine classification based on low molecular weight phenolic compounds

Background and Aims: Phenolic compounds influence colour, flavour and astringency of wines. Technology and grape variety are the main factor affecting the phenolic content of wines. Different multivariate statistical approaches were used to investigate the relationships between the profile of phenolic compounds and grape variety and also the impact of malolactic fermentation (MLF). Methods and Results: A reversed phase liquid chromatography/diode array detection method was used for the analysis of major non‐flavonoid phenolic compounds in wines from Trincadeira, Aragonez, Cabernet Sauvignon, Alfrocheiro, Casteão and Touriga Nacional varieties before and after MLF. The impact of MLF and grape variety on phenolic profile was evaluated by principal component analysis (PCA), variation partitioning analysis (VPA) and artificial neural network (ANN). PCA explained 86.5% of the total variance among samples. ANN showed a significant clustering of samples according to grape variety and confirmed that MLF has a minor effect on wine phenolic profile. VPA enabled more information to be extracted from the data by identifying explanatory variables responsible for variability among samples. Conclusions: Compared with PCA and ANN, VPA provides more information concerning the variability on the sample system. Also, grape varieties have a more effective impact on wine low molecular weight phenolic compounds than MLF. Significance of the Study: Each one of the three multivariate statistical approaches showed ways of analysing large chemistry experimental datasets. VPA is a step forward in data analysis, providing more solid and complete assessment of sample system variability, not possible by PCA and ANN.