EFFECT OF pH AND ASCORBIC ACID ON HIGH HYDROSTATIC PRESSURE-PROCESSED MANGO PUREE

Mango puree containing ascorbic acid (AA) (500 ppm) standardized at low pH (3.5) with phosphoric acid and inoculated or noninoculated with Saccharomyces cerevisiae was treated at high pressure (207, 345, 483 and 552 MPa) for selected times. High hydrostatic pressure (HHP)‐processed (552 MPa/5 min) standardized mango puree (SMP) was stored at 3C for 1 month and periodically analyzed for color, residual polyphenoloxidase (PPO) activity and microbial load. The remaining PPO activity average in SMP, after HHP processing at 207, 345, 483 and 552 MPa, at all times, was 35.8 ± 6, 21.5 ± 13.2, 46.8 ± 53.2 and 61.8 ± 5.8% PPO activity units, respectively. The D₂₀₇ values of 8.5 and 7.2 min for total count and yeasts were observed, respectively, after 207 MPa of pressure. A log reduction of 1.62 and 1.35 was observed after applying 345 MPa of pressure (2 s) for total count and yeasts, respectively. However, no microbial growth (<10 cfu/g) was observed after applying 483 or 552 MPa at any time. The addition of AA and the standardization at pH 3.5 reduced the rate of browning during storage.     

Effect of Peeling on Total Phenols, Total Glycoalkaloids, Discoloration and Flavor of Cooked Potatoes

The effect of peeling on the total phenols, total glycoalkaloids (TGA), discoloration, and flavor of 50–80g sized cooked potatoes was studied. Three methods of cooking were studied; (1) boiling in distilled water; (2) boiling in 16% NaCl solution; and (3) steaming. In all three methods, potatoes cooked without the peel were lower in phenolic and TGA content, discolored less, and were less bitter than potatoes cooked with the peel. During cooking phenols migrated from the peel into both the cortex and internal tissues of the potato. Glycoalkaloids were less mobile than phenols and migrated only into the cortex. The movement of phenols and TGA into the cortex increased both discoloration and bitterness in potatoes cooked with the peel.     

AN EVALUATION OF THE ALLEGHENY COUNTY NEIGHBORHOOD PRESERVATION PROGRAM

The Allegheny County Neighborhood Preservation Program has generated over five million dollars worth of housing rehabilitation in the three years in which it has been operating. This article is an evaluation of Phase 1 of the program. It compares loan recipients and non-recipients in order to determine which of the program components are the most important, which factors influence a household's investment decision, and what effect investment has on the perceptions of residents regarding the quality of both housing and the neighborhood.     

ANTIOXIDANT ACTIONS OF FRUIT, HERB AND SPICE EXTRACTS

The antioxidant properties of extracts of five fruits (apple, pear, peach, plum and grapefruit), three herbs (rosemary, tarragon and basil) and one spice (black pepper) were evaluated in a series of assays involving reactive oxygen species (ROS). In general, the crude extracts possessed potent antioxidant properties in vitro . Rosemary extract was 50-times more effective at preventing microsomal lipid peroxidation of human liver microsomes induced by NADPH/iron compared to peroxidation induced by iron/ascorbate, but tarragon was more effective in the iron/ascorbate dependent peroxidation. Analysis of the content of hydroxycinnamic acids of the pear, apple, plum and peach extracts measured after hydrolysis with sodium hydroxide showed that caffeic acid, p-coumaric and ferulic acids were the principal hydroxycinnamic acids present. Although the hydroxycinnamic acids and naringin do not contribute to the inhibition of lipid peroxidation by fruit extracts, they were able to inhibit deoxyribose degradation by 30% suggesting ability to weakly scavenge hydroxyl radicals (OH). Nevertheless, extracts of herbs and spices are increasingly of interest in the food industry because they retard oxidative degradation to lipids.     

INFLUENCE OF GEL NETWORKS IN CONTROLLING CONSISTENCY OF O/W EMULSIONS STABILISED BY MIXED EMULSIFIERS

A coherent explanation is presented of the mechanisms by which mixed emulsifiers of the surfactant/fatty alcohol type both stabilise and control the consistencies of oil-in-water emulsions. Original and published data are used to develop a theory in which the semisolid and other flow properties of emulsions are related to the nature, strength and extent of viscoelastic networks present in the continuous phases. These networks form from the interaction of surfactant solution with fatty alcohol and have similar properties to ternary system gels formed when the mixed emulsifiers disperse in water, in the absence of an oil. The theory is discussed with particular reference to liquid paraffin-in-water emulsions prepared with the surfactants anionic sodium dodecyl sulphate, cationic alkyltrimethylammonium bromides or non-ionic cetomacrogol and fatty alcohols cetyl and stearyl and their mixtures, especially cetostearyl. It may be used also to explain the properties of emulsions prepared with a variety of oils, surfactants and amphiphiles. The effects of variation in storage time, surfactant type (ionic or non-ionic), temperature, mixed emulsifier concentration, and alcohol and surfactant chain lengths on the rheological and microscopical properties of ternary systems and emulsions support this theory. The importance of small strain experiments (creep and oscillatory) in providing a true measure of consistency is emphasized. Continuous shear experiments, although theoretically less satisfactory, provide useful additional information when correlated with the small strain data.     

Stability of Proteinase Inhibitors in Potato Tubers During Cooking

Three proteinase inhibitors, Inhibitor I (a chymotrypsin inhibitor), Inhibitor II (a chymotrypsin and trypsin inhibitor), and Carboxypeptidase Inhibitor were quantified immunologically in extracts of various tissues of Russet Burbank potato tubers and were monitored over various intervals during boiling (30 min), oven baking (80 min, 191°C) and microwave baking (7 min) to assess the effectiveness of cooking in denaturing the potentially toxic proteins. In cooked tubers, Inhibitor II was completely inactivated during all cooking treatments and Inhibitor I was partially inactivated, depending upon the cooking method. The Carboxypeptidase Inhibitor was extraordinarily stable during all of the cooking conditions. Overall, microwave baking was most effective for cumulatively inactivating Inhibitor I and Inhibitor II. The unusual stability of CPI to all types of cooking raises questions concerning the effect of this inhibitor on the total digestibility of cooked potato proteins.     

Restructured Reindeer Steaks: Effects of Flake Size, Phosphate, and Salt on Sensory Properties

Steaks, fabricated from forequarters from field-slaughtered Alaskan reindeer, were prepared from meat flaked to two sizes (1.295 and 1.905 cm), with (0.5%) and without phosphate, and with (0.5%) and without salt. Phosphate did not appreciably affect sensory properties. Larger flakes and salt improved quality and acceptability, therefore, additional steaks were fabricated from meat flaked with a larger cutting head (4.064-cm) and with three levels of salt (0.0, 0.5 and 0.75%). Steaks containing 0.75% salt were less chewy, softer, juicier, and more acceptable than those made with 0.5% salt but did not differ from those containing no salt. Feasibility of producing restructured steaks from reindeer forequarters was demonstrated.     

Cloud classification from satellite data using a fuzzy sets algorithm: A polar example

Abstract

Where spatial boundaries between phenomena are diffuse, classification methods which construct mutually exclusive clusters seem inappropriate. The fuzzy c-means (FCM) algorithm assigns each observation to all clusters, with membership values as a function of distance to the cluster centre. The FCM algorithm is applied to Advanced Very High Resolution Radiometer (AVHRR) data for the purpose of classifying polar clouds and surfaces. Careful analysis of the fuzzy sets can provide information on which spectral channels are best suited to the classification of particular features and can help determine likely areas of misclassification. General agreement in the resulting classes and cloud fraction was found between the FCM algorithm, a manual classification and an unsupervised maximum likelihood classifier.     

Tail-recursive Distributed Representations and Simple Recurrent Networks

Representation poses important challenges to connectionism. The ability to compose representations structurally is critical in achieving the capability considered necessary for cognition. We are investigating distributed patterns that represent structure as part of a larger effort to develop a natural language processor. Recursive auto-associative memory (RAAM) representations show unusual promise as a general vehicle for representing classical symbolic structures in a way that supports compositionality. However, RAAMs are limited to representations for fixed-valence structures and can often be difficult to train. We provide a technique for mapping any ordered collection (forest) of hierarchical structures (trees) into a set of training patterns which can be used effectively in training a simple recurrent network (SRN) to develop RAAM-style distributed representations. The advantages in our technique are three-fold: first, the fixed-valence restriction on structures represented by patterns trained with RAAMs is removed; second, the representations resulting from training correspond to ordered forests of labeled trees, thereby extending what can be represented in this fashion; third, training can be accomplished with an auto-associative SRN, making training a much more straightforward process and one which optimally utilizes the n-dimensional space of patterns.     

The optimal adaptive control law for a linear plant with unknown input gains†

The optimal adaptive control law is determined for a dynamic, linear, discrete-time system with unknown input gains when regulation of the state is desired. The expectation of a quadratic cost is minimized. The solution is obtained by extending some of the results of the dual control theory so as to apply to the given problem.