Effects of Lactobacillus rhamnosus GG addition in ice cream

A 2⁴ full factorial experimental design was applied to verify the effects of Lactobacillus rhamnosus GG (LGG) addition in retail-manufactured ice cream stored at two different freezing temperatures (−16°C and −28°C) and containing two different levels of sugar (15–22%) and fat (5–10%). In addition to microbial counts, the pH, acidity, viscosity of the mixes and functional properties of the ice creams were evaluated. Both fresh and frozen-thawed LGG cells underwent preliminary resistance tests to bile, antibiotics and acidity. The LGG strain proved to be highly resistant to most of the stress factors. When the micro-organism was added to ice cream mixes in a quantity of 10⁸ cfu/g, it did not change the overrun, firmness or melting behaviour of the finished product. Regardless of formulation, no count decay of LGG cells was observed in ice cream stored for up to 1 year.     

INCLUDING CHESTNUTS AND SUGAR BEET PULP IN DIETS FOR PIGS: THE EFFECTS ON THE QUALITY OF PORK MEAT AND THE SENSORY PROPERTIES OF DRY-CURED SAUSAGE (CHORIZO GALLEGO)

This research was aimed at evaluating how the inclusion of dried chestnuts and dried sugar beet pulp in diets for pigs affected the quality of pork meat and the sensory properties of dry-cured sausage ( chorizo gallego ). The meat from pigs that received a diet with chestnuts and sugar beet pulp (CBP) showed lower thiobarbituric acid values and higher water-holding capacity than meat from pigs fed a conventional diet (C). Significant differences were also observed between both batches in color parameters and fatty acid composition of the meat. In the sensory analysis of chorizo, the sausages manufactured with meat from pigs fed the CBP diet were significantly better rated than those with meat from pigs fed a C diet in appearance, odor, flavor, texture and overall score.

PRACTICAL APPLICATIONS

The inclusion of dried chestnuts and dried sugar beet pulp in diets for pigs during the fattening period allowed us to recover some of the ingredients more traditionally used in the feeding of pigs. This inclusion modifies some parameters of the resulting pork meat quality; (it decreases lipid oxidation and increases water-holding capacity and polyunsaturated fatty acid content) and also improves the sensory properties of any dry-cured product made with this pork meat.     

PHASEOLIN RFLP IN BEAN (PHASEOLUS VULGARIS) CULTIVARS

A 0.5 kbp phaseolin gene fragment was used as a probe to study phaseolin restriction fragment length polymorphism (RFLP) in P. vulgaris cultivars. Results obtained from plants displaying type S and type T phaseolin suggest a genomic organization more variable than that previously described. This variability could be exploited to aid gene identification as well as to improve germ plasm bank organization. The same probe was useful in detecting phaseolin linked RFLP in other leguminosae.     

FOAM-MAT FREEZE-DRYING OF APPLE JUICEPART 1: EXPERIMENTAL DATA AND ANN SIMULATIONS

Freeze-drying of foamed and nonfoamed apple juice was studied in order to assess if there is a reduction in process time due to foaming. Foams were prepared by whipping apple juice with methylcellulose or egg albumin at different concentrations. Foamed and nonfoamed juice samples having different thickness and different initial weight were frozen at −40C and then freeze-dried at 20C during 48 h under vacuum. Sample weight loss and temperature were followed at different process times. A mathematical model based on artificial neural networks was developed to represent foam kinetics and temperature curves during freeze-drying. Foaming reduced process time if the comparison was done at equal sample thickness. However, lower density of foamed materials decreases weight load to the dryer. Unfortunately, the optimization of the process did not permit the determination of a practical minimal foam sample thickness to enhance both drying rate and dryer throughput.

PRACTICAL APPLICATIONS

Fruit juice powders have a large application in the food and nutraceutical industries. These powders are used as instant beverages, ingredients for bakery or extruded products and to incorporate in pharmaceutical tablets. Freeze-drying is an excellent process to obtain a high-quality fruit juice powder because it offers extraordinary nutritional, structure and sensorial qualities when compared with products of alternative drying process: air, vacuum, microwave and osmotic drying. However, the process cost is expensive due to the long drying times under vacuum. Process acceleration through optimization is therefore necessary in order to obtain high quality in the final products but at lower costs. This study aims to decrease the cost of the freeze-drying process by using foaming prior to processing to increase the drying rate.     

Natural Convection in an Array of Vertical Channels with Two-Dimensional Heat Sources: Uniform and Non-Uniform Plate Heating

An experimental and numerical analysis was performed to investigate the conjugated conduction–convection heat transfer problem in an array of vertical, parallel plates forming open channels with heated protruding elements attached to one of the walls. Uniform and non-uniform heating of the plates was analyzed. Both the distance between plates and power dissipated per plate was varied. In non-uniform heating in each plate and for a specified total heat generation rate, one element was electrically supplied with a different power level from the others, and the influence of the location of this element on the temperature distribution was investigated. The SIMPLEC algorithm, based on the finite volume method, was used to solve the pressure velocity coupling. Numerical and experimental temperature profiles were compared and good agreement was observed.