Cocoa Seeds: Changes in Protein and Polysomal RNA During Development

Amounts of soluble protein increased three- to four-fold while microsomal protein and polysomal RNA levels decreased by similar factors in cocoa seed extracts at different times during the developmental period of rapid cotyledon growth to fruit ripening. During early development, up to 90% of translatable mRNA was poly A(?). In mature seeds this decreased to about 75%. The radioactive polypeptides synthesized by a. wheat germ in vitro translation system were the same whether the system was programmed with poly A(?) or poly (A+) RNA. Polypeptides synthesized in the in vitro translation system were electrophoretically similar to those extracted from intact seeds, testimony to the integrity of isolated messenger RNA.     

MEAT QUALITY ATTRIBUTES OF CHILLED VENISON AND BEEF

ABSTRACT

Meat quality attributes of venison and beef “semimembranosus” muscle stored at ?1.5 C for 4 weeks were compared. Chilled venison had lower L*, a*, b*and chroma compared to beef. Percent expressible water (PEW), shear force and cook loss were lower in venison compared to beef. μ‐Calpain activities at pH 7.4 and 5.5 were higher and the activity of μ + m‐calpain at pH 5.5 (and not at pH 7.4) was lower in venison compared to beef. L*, a*, b*and chroma in meat from both species increased with chilled storage time (P < 0.01); the increase was higher in beef compared to venison. μ‐Calpain activities at pH 7.4 and 5.5 in venison increased in the first week of storage and then declined in the second while it decreased with time in beef at pH 7.4 and followed similar trend as venison at pH 5.5. Activities of μ + m‐calpain at pH 7.4 and 5.5 decreased with chilled storage time in both types of meat. Shear force decreased with storage time, raw meat PEW increased in the first week and cook loss increased for the first 2 weeks of storage and then declined thereafter in both meats. Within the parameters of this study, the table‐eating quality of venison improved and its color deteriorated faster in chilled storage compared to beef implying that the processing inputs required to maximize meat quality of beef may not be suitable for venison and vice versa.

PRACTICAL APPLICATIONS

The following are some of the practical applications of this research: (1) process variables for optimal quality of table beef and venison differ, processors should tailor their process specifically for each specie; (2) venison producers who supply distant markets should consider the rapid rate of tenderization of venison to avoid supplying products with poor texture resulting from over tenderization; (3) the practice of packaging meat under high oxygen environment to enhance color may affect the quality of venison more than other red meats because of the rapid rate of oxidation in venison relative to these meats; (4) the rapid deterioration in the color of venison underscored the need to come up with a way of convincing the consumer to accept the browner color of venison as an inherent characteristic of this meat in order to minimize any bias against the meat because of its color; and (5) the use of fluorogenic substrates for determining calpain activities if further validated in other studies can be used for the online prediction of tenderness early postmortem.

     

Using a <670> zone axis for convergent beam electron diffraction measurements of lattice strain in strained silicon

Convergent beam electron diffraction patterns of silicon from the gate channel region of a complementary metal‐oxide‐semiconductor transistor with recessed Si_.82Ge_.18 stressors were analysed using three zone axes: <230>, <340> and <670>. Values measured using these axes were compared with each other with regards to strain along the [] and the [001] directions. It was demonstrated that strain measurements made using all three axes showed reasonable agreement with each other: an increase in the [] compressive strain and a switch from compressive to tensile strain in the [001] with decreasing distance below the gate. It was also observed that the strain calculations using the <230> axis had the lowest uncertainty whereas the <670> axis allowed for measurements closest to the gate due to the improved lateral resolution at that tilt angle.     

DIFFERENTIATION OF BREWERY YEAST STRAINS BY DNA FINGERPRINTING

A reliable and reproducible non-radioactive DNA fingerprinting technique has been used to differentiate between twelve production brewery yeast strains. The method comprises total DNA preparation from the yeast strains, enzymatic digestion of the DNA and analysis of the DNA fragments by “probing” with known DNA labelled with the plant steroid digoxigenin. A range of probes and several enzymes have been investigated. A successful combination is the restriction endonuclease Hind III and a probe derived from Ty1 (a yeast transposable element). The main advantages of this method are its unambiguity, reproducibility and suitability for routine brewery QC use.     

KCI, CaCI2, Na+ Binding, and Salt Taste of Gum Systems

Aqueous nonionic (0.3% w/v) and ionic (0.1% and 0.3% w/v) gum systems containing NaCl, or equal weights of NaCl plus KCl, or NaCl plus CaCl, were examined. At equivalent molar concentrations of added ions, ²³Na NMR transverse relaxation rates (R₂, set^?1) showed an increase in average Na⁺ mobility with the addition of K⁺ or Ca²⁺ to ionic gum systems. Correspondingly, salt taste increased with addition of KCl as determined by Decision Boundary modeling of subject identification data. Viscosity did not affect saltiness. Na⁺ was free to induce salt taste when K⁺ was bound to the gum. Enhancement of salt taste by KCl is due, in part, to competitive binding of Na⁺ and K⁺ in a system.     

EFFECT OF SOLUBLE SOLIDS AND TEMPERATURE ON ASCORBIC ACID DEGRADATION IN LEMON JUICE STORED IN GLASS BOTTLES

Lemon juice at concentrations of 9°, 20°, 30°, 40° and 50°Brix was stored at 10°, 20° and 36°C for 16 weeks and sampled regularly for total soluble solids (TSS), pH, titratable acidity and ascorbic acid. No significant differences were found in the first two of these factors as a function of storage time. There was a small but significant decrease in citric acid concentration over 16 weeks. Ascorbic acid loss was greater at higher temperatures; at a constant temperature, the loss was smaller as TSS increased. Ascorbic acid degradation data fitted zero-, first- and second-order models equally well at all five TSS. Rate constants in 9°Brix juice were significantly higher than those for the other four concentrations at all three temperatures. E_a values of 47.8 and 24.1 kJ mol^?1 were calculated for ascorbic acid degradation in 9° and 20°Brix juices. The effect of temperature far outweighed the effect of TSS on ascorbic acid degradation. Over the 16-week storage period, maximum retention of ascorbic acid (95.7%) was obtained in the 50°Brix lemon juice concentrate stored at 10°C.     

Regional classification of New Zealand red wines using inductively-coupled plasma-mass spectrometry (ICP-MS)

Red wines in a dataset of 120 single-region wines could be classified into seven of the major New Zealand winegrowing regions with an overall accuracy of 80.8% using leave-one-out linear discrimination with the elements Sr, Rb, Ni, Co, Pb, Mn, Cd, Ga and Cs. A higher classification accuracy of 94.4% was achieved when regions were combined into North Island, Nelson, and other South Island regions. The rare earth elements did not prove useful for regional classification, both because of their low and variable concentrations and because their concentrations can be increased upon bentonite fining. Wines originating in the Gimblett Gravels Winegrowing District could be discriminated from wines grown in the remainder of the Hawke's Bay region with a high degree of accuracy using Ba, Cs, Rb, and Pb. A small difference in elemental composition between Pinot Noir, Cabernet Sauvignon, and Merlot wines originating from the Hawke's Bay region was observed. However, despite this difference greater classification accuracy was obtained with a database containing all the red wines than a subset containing only Pinot Noir wines.     

A THEORETICAL MODEL FOR COMBUSTION REACTIONS INSIDE A REFRACTORY TUBE

A kinetic and thermal model has been developed for the evaporation and combustion of a single chain of uniformly sized droplets of hexane in a turbulent stream of air inside a refractory tube. A single global rate expression is utilized for the oxidation of hexane to CO and H₂0, but 44 reversible, free-radical mechanisms thereafter. Adiabatic flow is postulated for the post-flame zone and plug flow throughout. An integro-differential energy balance for the wall is avoided by the use of an experimental wall temperature profile for each set of conditions. The model is restricted to external conditions such that evaporation is completed prior to ignition. Calculated concentrations of NO are in good agreement with measured values for fuel-lean mixtures over a wide range of post-flame residence times. Calculated concentrations of CO are up to twice as high as experimental values but demonstrate the same dependence on residence time and equivalence ratio, suggesting that some of the individual rate constants are incorrect. The predictions for both NO and CO are a great improvement over those of prior, simplified models, The predictions of NO deviate increasingly from measured values as the equivalence ratio increases above unity, undoubtedly due to the inapplicability of the global model for the oxidation of rich mixtures of hexane.

The assumption of a pseudo steady state concentration was not found to be valid for any of the free radicals of the detailed model, thereby accounting for the inaccuracy of the various simplified models for the production of NO and the oxidation of CO.