Hydrophobicity and Solubility of Meat Proteins and Their Relationship to Emulsifying Properties

Surface hydrophobicity (S_o) of crude salt extracts of meat was determined fluorometrically using cis-parinaric acid as a probe. Upon heating the extracts to 70°C, S_o increased two- to threefold, whereas protein solubility (s) decreased to 20%. Further heating (to 85°C) resulted in slight decreases in both S_o and s. Backwards stepwise multiple regression equations for prediction of emulsifying activity index (EAI) and emulsifying capacity (EC) were: EAI = 2.658 + 0.0001308 sS_o, and EC =−35.30 + 6.459 s + 0.001317 sS_o− 0.05463 s². S_o was most important for predicting emulsifying properties of samples with high (>50%) solubility, whereas solubility parameters were more influential for samples with low (<50%) solubility.     

THE EFFECT OF TURBULENT MIXINGON PHYSICOCHEMICAL ABSORPTION NEAR INTERFACES*

A novel approach to physicochemical absorption is developed which yields a priori estimates of enhancement factors. The theory is applied to solid-fluid/fluid-fluid interfaces for irreversible first-order kinetics. The results of these theoretical calculations are compared to other models and existing experimental data.     

Discrete cell control

This paper outlines the approach taken by the Cell Control Group at the University of Birmingham, in collaboration with four industrial partners, to define the generic elements of a discrete cell controller. The research programme has determined the functions which should be performed at cell level, and established how the cell controller should communicate both upwards to manufacturing information systems and downwards to the machine controllers on the shop floor.     

Formal proof for the constant trace forgetting factor

In recent literature, the bounds on a constant trace forgetting factor used with a standard weighted least-squares identification have been stated, based on heuristic considerations. A formal proof for these bounds is presented.     

MONITORING OF SIGNALS FROM MANUFACTURING PROCESSES USING THE KARHUNEN–LOÈVE TRANSFORM

Monitoring the condition of signals during manufacturing can provide valuable information about the status of the parts being produced, as well as that of the components of the manufacturing machine. To this end, we introduce a monitoring technique based on the Karhunen–Loève transform, which decomposes measured manufacturing signals into decorrelated components in the form of fundamental eigenfunctions. The isolated eigenfunctions are monitored by means of the corresponding coefficient vectors, which indicate stationary and non-stationary changes in the deterministic and stochastic fundamental patterns. In this paper, the mathematical foundations of the technique are explored to form a good understanding of the mechanics of the transformation. This understanding is achieved with simple illustrative examples in the discrete and continuous domains, followed by an example of multicomponent signal decomposition by means of numerical simulations. The monitoring potential of the technique is illustrated with an example from a milling process, where the main modes are extracted by means of the eigenvectors and coefficient vectors.     

The Self-Protection of Escherichia Coli in Seawater

Many environmental variables are known to be involved in the inactivation processes affecting enteric bacteria in seawater. It is commonly believed that bacteria may attempt to reduce adverse effects by adhering together, thereby decreasing the surface area exposed to the hostile environment. This mechanism may be described as self-protection and should enhance the survival of the bacterial population.
Controlled laboratory experiments, epifluorescence microscopy, and Coulter counter analysis were used to examine and elucidate the inactivation mechanisms for the enteric bacterium E. coli. In general, the survival of E. coli was found to be enhanced with increasing initial cell concentration in the absence of any suspended solids.     

Pilot scale preparation of wheat gluten protein fractions I-Influence of process parameters on their protein composition

Commercial wheat gluten was fractionated on a pilot plant scale to produce gliadin-and glutenin-rich fractions. Acetic acid solutions (0.01–0.05 M) were blended with dry gluten (16, 10 or 7 volumes unit^-1 of dry gluten ratio) and the slurry was separated by continuous centrifugation to yield a gliadin-rich supernatant, which was then concentrated by ultrafiltration and spray-dried. the pellet obtained was optionally rinsed by water or acetic acid and separated in a second stage. the second supernatant was treated as the first one, and the final residue, insoluble and glutenin-rich, was then dispersed in ammonia and spray-dried. the protein distributions in supernatants and residues depended on pH and ranged from 20/80 to 40/60 for the first stage, and from 40/60 to 80/20 for the sum of the two stages. the compositions of the fractions were measured by solubility tests and size exclusion high performance liquid chromatography (SE-HPLC) profiles. A [-1, +1] selectivity scale was created: each fraction was compared to pure gliadins (-1), gluten (0) and pure glutenins (+1). the best combination between yields of soluble and insoluble fractions (40/60 distribution) and selectivities for gliadins and glutenins (-0.32 and +0.26 respectively) was obtained at ratio 16 and a 0.01 M molarity. Though the selectivities were limited because gliadins and medium-size glutenin polymers have similar solubilities in acid solutions, this process permits preparation of fractions which differ widely from gluten in contents of high molecular weight glutenin polymers.     

Glottal closure instant and voice source analysis using time-scale lines of maximum amplitude

¹Time-scale representation of voiced speech is applied to voice quality analysis, by introducing the Line of Maximum Amplitude (LoMA) method. This representation takes advantage of the tree patterns observed for voiced speech periods in the time-scale domain. For each period, the optimal LoMA is computed by linking amplitude maxima at each scale of a wavelet transform, using a dynamic programming algorithm. A time-scale analysis of the linear acoustic model of speech production shows several interesting properties. The LoMA points to the glottal closure instants. The LoMA phase delay is linked to the voice open quotient. The cumulated amplitude along the LoMA is related to voicing amplitude. The LoMA spectral centre of gravity is an indication of voice spectral tilt. Following these theoretical considerations, experimental results are reported. Comparative evaluation demonstrates that the LoMA is an effective method for the detection of Glottal Closure Instants (GCI). The effectiveness of LoMA analysis for open quotient, amplitude and spectral tilt estimations is also discussed with the help of some examples.     

SOLUBILITY AND EMULSIFYING PROPERTIES OF KAPPA CASEIN AND ITS CASEINOMACROPEPTIDE

Kappa-casein A was treated with chymosin in order to isolate the caseino-macropeptide corresponding to the C-terminal 106–169 residues of K-casein. Whole casein, K-casein and the caseinomacropeptide (CMP) were studied for their water solubility and emulsifying activity. The CMP was soluble over the range of pH from 1 to 10, with a "minimum" solubility (88%) in the range of pH 1–5 and a "maximum" solubility (98%) in the range of pH 5–10. For whole casein and K-casein, at pH values above 5.5, the emulsifying activity increased when pH increased and the maximum value was obtained for very alkaline solutions; for pH values below 4.5, the increase in emulsifying activity was much more pronounced at pH 2.5; below pH 2.5, emulsifying activity decreased. For CMP, the increase in emulsifying activity was much more pronounced in the acidic range than in the alkaline range. After 24 h storage and heating of the emulsion, a large pH-dependant decrease of emulsifying activity (22–60%) was observed for CMP for pH values below 4.0; under the same conditions, the emulsifying activity of whole casein and K-casein showed a 5–19% and a 1–21% decrease, respectively. For pH values above 6.0, a 22–59% decrease was observed for CMP as compared to a 1–12% and a 4–17% decrease with whole casein and K-casein, respectively.     

Control of Lipid Oxidation in Cooked Ground Pork with Antioxidants and Dinitrosyl Ferrohemochrome

A number of antioxidants were added to ground meat prior to cooking to achieve oxidative stability. The 2-thiobarbituric acid (TBA) numbers of cooked-meat samples after storage for up to 35 days were determined. Of the antioxidants tested, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), propyl gallate (PG), t-butylhydro-quinone (TBHQ), trihydroxybutyrophenone (THBP), nordihydro-guaiaretic acid (NDGA), catechol, and ethoxyquin were effective at a level of 200 ppm giving TBA values of less than one. BHA, TBHQ, and ethoxyquin were equally effective at a level of 30 ppm. Ascorbyl acetal and ascorbyl palmitate retarded lipid oxidation effectively (TBA values of slightly over one after five weeks of storage). The cooked cured-meat pigment showed some antioxidant effect which increased with increasing concentration, and at 18–24 ppm was better than that of 200 ppm of α-tocopherol.