Determining the Odor Thresholds for Some Compounds in Alcoholic Beverages

SUMMARY: Determinations have been made of the sensory odor threshold estimates of four alcohols, five esters, seven acids and diacetyl found in alcoholic beverages, by means of the triangular test. The threshold levels ranged among alcohols from 5 to 8 ppm except for isobutyl alcohol with the level of 75 ppm. Among esters there were three with the level of 0.2-0.6 ppm and two with the level of 14-17 ppm. Among acids three levels were found, one with the range of 4-9 ppm, one with 15-20 ppm and isovaleric acid with 0.7 ppm. Diacetyl had the lowest level–0.0025 ppm. The determination of thresholds was standardized by calculation of the percentage-abovechance-scores; by testing the usefulness of the amateur panel, and by specification of the threshold estimates in statistical terms. The results attained a fair goodness-offit of the model and the smell perception was found to vary with the logarithm of the stimulus. The distribution of scores follows the normal probability function.     

CHARACTERIZATION OF TIME DEPENDENT FLOW PROPERTIES OF MAYONNAISE UNDER STEADY SHEAR

Time dependent flow properties of commercial mayonnaise have been measured at shear rates of 0.530, 0.169, 0.052, and 0.0169 s⁻¹. The flow curves were fitted with a series of two first order rate functions. It appears that the time dependent flow properties of mayonnaise are better characterized by this model than with only the initial and final stress values of the stress decay curves or with a single first order rate function.     

Current Status of Hybrid Bearing Damage Detection

Advances in material development and processing have led to the introduction of ceramic hybrid bearings for many applications. The introduction of silicon nitride hybrid bearings into the high-pressure oxidizer turbopump on the space shuttle main engine led NASA to solve a highly persistent and troublesome bearing problem. Hybrid bearings consist of ceramic balls and steel races. The majority of hybrid bearings utilize Si₃N₄ balls. The aerospace industry is currently studying the use of hybrid bearings and, naturally, the failure modes of these bearings become an issue in light of the limited data available.

In today's turbine engines and helicopter transmissions, the health of the bearings is detected by the properties of the debris found in the lubrication line when damage begins to occur. Current oil debris sensor technology relies on the magnetic properties of the debris to detect damage. Because the ceramic rolling elements of hybrid bearings have no metallic properties, a new sensing system must be developed to indicate the system health if ceramic components are to be safely implemented in aerospace applications. The ceramic oil debris sensor must be capable of detecting ceramic and metallic component damage with sufficient reliability and forewarning to prevent a catastrophic failure.

The objective of this research is to provide a background summary on what is currently known about hybrid bearing failure modes and to report preliminary results on the detection of silicon nitride debris in oil using a commercial particle counter.     

Effects of Food Gums on Zinc and Iron Solubility following in vitro Digestion

The effects of three levels (0.1, 0.3 and 0.5%) of locust bean gum, guar gum and sodium alginate on zinc and iron availability were evaluated in milk and soy systems. Availability was estimated as metal solubility after digestion with pepsin-HCl followed by addition of bicarbonate and digestion with pancreatic and bile extracts. Locust bean gum (0.5%) and guar gum (0.5%) reduced zinc solubility by 23.5 and 69.6%, respectively, in the milk and by 41.1 and 40.1% in the soy. Smaller reductions were observed at lower gum levels. The two gums also caused significant reductions in iron solubility from soy. Sodium alginate exerted little effect on mineral solubility.     

Hydroxyapatite-alginate biocomposite promotes bone mineralization in different length scales in vivo

Tissue engineering is a multidisciplinary research area that aims to develop new techniques and/or biomaterials for medical applications. The objective of the present study was to evaluate the osteogenic potential of a composite of hydroxyapatite and alginate in bone defects with critical sizes, surgically made in the calvaria region of rats. The rats (48 adult males), Rattus norvegicus Wistar, were divided into two groups: control (without composite implantation) and experimental (with composite implantation) and analyzed by optical microscopy at the biological time points 15, 45, 90 and 120 d, and transmission electron microscopy 120 d after the implantation of the biomaterial. It was observed that the biomaterial presented a high degree of fragmentation since the first experimental points studied, and that the fragments were surrounded by new bone after the duration of the project. These areas were studied by analytical transmission electron microscopy using an energy dispersive X-ray spectrometer. Three regions could be distinguished: (1) the biomaterial rich in hydroxyapatite; (2) a thin contiguous region containing phosphorus but without calcium; (3) a region of initial ossification containing mineralizing collagen fibrils with a calcium/phosphorus ratio smaller than the particles of the composite. The intermediate region (without calcium or containing very low amounts of calcium), which just surrounded the composite had not been described in the literature yet, and is probably associated specifically to the biocomposite used. The high performance of the biomaterial observed may be related to the fact that alginate molecules form highly anionic complexes and are capable of adsorbing important factors recognized by integrins from osteoblasts. Regions of fibrotic tissue were also observed mainly in the initial experimental points analyzed. However, it did not significantly influence the final result. In conclusion, the biomaterial presents a great potential for application as bone grafts in the clinical area.     

A PRACTICAL APPROACH TO PREPARATION AND MEAT PRESERVATION BY REFRIGERATION OR FREEZING OF THE LAND SNAIL (HELIX ASPERSA MÜLLER)

Helix aspersa Müller is one of the few land snails suitable for preparation for human consumption, and constitutes an important potential alternative for mass production of animal protein. High-quality meat obtained from this snail can compete with cattle, swine and poultry because of its comparatively lower production costs of infrastructure, labor and feeding. The objective of the study is to present information on initial processing steps for this product, where mucus (slime) is eliminated from the snails. Concentrations of salt and vinegar over periods of time required for elimination of slime after the purging step were determined, permitting uninterrupted continuation of the preparation process before its refrigeration and freezing storage. Optimal slime elimination was achieved by following a statistical design based on a 2³ factorial scheme as a variable response to weight loss, indicating elimination of the slime. The results obtained showed the best concentration of salt to be 7.5% and vinegar 10%, with an immersion time of 45 min. Moreover, some preliminary aspects related to refrigeration and freezing rate process are also delivered.

PRACTICAL APPLICATIONS

The results of this study indicate that there is a practical way to eliminate the Helix aspersa Müller slime in order to obtain a cleaner meat, using acid salt solutions at room temperature with low-cost additives, including common salt and white vinegar, allowing the low- and median-capacity industries to have access to a simple technology in the preliminary operations of the production process. Furthermore, the product obtained could undergo the preservation processes with or without the shell, where the boiling-in-water operation could be included or not. Finally, it could be preserved by refrigeration or freezing.     

Improving Thematic Mapper land cover classification using filtered data

In an attempt to alleviate the classification problems introduced by the higher spatial resolution of the Thematic Mapper in comparison to the Muitispectral Scanner, classifications were performed on two to six band combinations, first using Thematic Mapper bands only, and subsequently replacing band 5 by its mean-filtered and median-filtered counterpart. The combination of filtered data with non-filtered data smooths out scene noise while retaining some of the boundary detail.     

THERMAL PROCESS CALCULATION USING ARTIFICIAL NEURAL NETWORKS AND OTHER TRADITIONAL METHODS

This work aimed to develop a method of thermal process calculation of canned food based on an artificial neural network and to compare it to the traditional Ball and Stumbo methods. A back‐propagation through time network was used as a model of heat conduction occurring in canned food, in order to predict the cold point temperature as a function of the autoclave and the initial product temperature. For training the network, a dataset of the cold point and retort temperature along time was obtained by processing a paste‐based product in autoclave. The network architecture (5‐8‐9‐1) was selected, presenting an excellent generalization capacity, with a mean relative error of 2.2% between the calculated F‐values of the observed and predicted time–temperature data. The Ball and Stumbo methods presented higher errors as the retort temperature was not constant. Neural network showed a great potential for online process calculation by having advantages such as precision and simplicity.     

A RESEARCH NOTE

Abstract Parsley and watercress samples acquired in street-markets in Rio de Janeiro were screened for the presence of Aeromonas on the day of the purchase without refrigeration and after 7 days of storage at 5C. Thirty-nine Aeromonas strains were isolated from both refrigerated and nonrefrigerated samples and were identified as A. caviae strains(21;5), A. hydrophila strains(1;6) and Aeromonas sp. strains(5;1) from watercress and parsley, respectively. Enterotoxin production, hemolysin, protease activity and resistance profiles were investigated among the strains isolated. Seventeen (51.5 %) Aeromonas strains were classified as enterotoxigenic. By employing "L" agar containing washed rabbit erythrocytes 16 (48.5%) hemolytic strains were detected. All strains analyzed were able to produce protease. Among strains evaluated 39% showed resistance to trimethoprim and 21 % to gentamicin. As these vegetables are usually consumed raw, they can pose a risk especially for immunocompromised individuals.