HIGH PRESSURE INACTIVATION OF SACCHAROMYCES CEREVISIAE,ENDOGENOUS MICROFLORA AND PECTINMETHYLESTERASE IN ORANGE JUICE1

Decimal reduction times (D-values) for Saccharomyces cerevisiae ascospores inoculated into pasteurized orang juice ranged from 4 to 76 s at pressures between 500 and 350 MPa. At the same pressures, D-values of S. cerevisiae vegetative cells ranged from 1 to 38 s while those for the native microflora in nonpasteurized Hamlin orange juice were between 3 and 74 s. Corresponding z-values were 123, 106 and 103 MPa for ascospores, vegetative cells and native microflora, respectively. Native microorganisms that survived high pressure treatments included yeasts, gram-positive and gram-negative bacilli. Pectinmethylesterase activity in nonpasteurized Hamlin orange juice was reduced to 5% of initial activity after 30 s at 900 MPa.     

GAS CHROMATOGRAPHIC DETECTION OF DIACETYL IN ORANGE JUICE

A GLC method was developed for detection of diacetyl (2,3-butanedione) and acetoin (3-hydroxy-2-butanone) in orange juice. Retention times for diacetyl and acetoin were 2.8 ± 0.03 and 6.8 ± 0.02 min, respectively. Concentration by distillation was essential to detect small quantities by GLC of diacetyl but was ineffective for acetoin. A linear response of diacetyl concentration to peak area was observed between 0.05 and 0.5 ppm. The peak areas at 0.05 and 0.5 ppm diacetyl were 1242 ± 203 and 20142 ± 1120, respectively. Elevating the column temperature and decreasing the carrier gas flow rate, increased the limit of detection for acetoin from ≥ 100 ppm to ≥ 10 ppm, but diminished the resolution of the diacetyl peak from juice volatiles.     

DIRECT PLATING: A METHOD FOR DETECTING FUNGAL CONTAMINATION IN PAPERBOARD CARTONS

Contamination of refrigerated juice products in gable-top cartons can occur by filamentous fungi that are present in the paperboard. A method was developed to assay the mycoflora of paperboard carton material used in beverage packaging. This method involved direct plating on an agar surface of 1 cm² carton pieces rather than disintegration of carton material in a blender prior to plating. When compared to the standard disintegration method traditionally used for monitoring contamination of paperboard, the new method is less cumbersome, more efficient, and reduces opportunities for contamination. The number of colonies produced by the direct plating method was greater than or equal to the modified standard disintegration method. Direct plating also resulted in a larger number of different genera isolated.     

URBAN REGIMES AND RACIAL POLITICS IN NEW ORLEANS

ABSTRACT: This paper describes and analyzes the nature of the New Orleans urban regime focusing on the first term of Sidney Barthelemy, the second black mayor of New Orleans (1986–1990). First, because the authors believe that regime theory needs to be more carefully theorized in relation to racial politics, they begin by discussing the changing relationship of blacks to the prevailing New Orleans regime. Second, in analyzing this racial politics, they focus on the relationship between the evolving structure of the electoral coalition, governing coalition development strategies, and the stability of the governing regime. They conclude that a caretaker regime is very difficult to maintain in a city with a recent majority black electorate. Such an electoral coalition has a tendency to support either a progressive or corporate regime. Finally, the authors pay particular attention to the development of the consensus-seeking para-apparatus, its relationship to racial politics, and its affect on development policy, governing coalition politics, and regime transition.     

TOWARD AN ALGEBRAIC GNOSEOLOGY

Abstract

In this paper we present a functional model of a portion of a mammalian brain. That is, a model that both simulates some of the anatomo-functional properties characterizing large pieces of the nervous tissue and imitates some of the, we hope fundamental, functional aspects of a whole brain. To test our picture we propose also some applications to an, admittedly, simplified universe. To aid in our task we shall use a version of a data-flow computer similar to the one previously introduced. Its associated language, at a syntactic level, has the algebraic structure of a free group. This allows us to systematically investigate the possibility to exploit the equations in such kind of structure. In other words, the free group is a kind of metaenvironment into which we can obtain procedures, operating upon procedures, via the juxtaposition and the inverse rules defined within the algebraic structure. To arrive at the formulation of our model, we begin with a discussion of the relevant data and notions about the structure and functioning of some nerve ganglion and of its ultimate component, the neuron. To simplify our exposition we refer almost exclusively to the most recent literature, but the reader is strongly urged to also look at the other works listed. In any case, we hope to have selected all the basic notions so that our picture of a functioning brain can still be acknowledged as a fair one. In conclusion, we are well aware that the model we outline here is probably nearer to the Lull's turning wheels than to reality.