EFFECT OF DIETARY SORGHUM DISTILLERY RESIDUE ON HEMATOLOGICAL CHARACTERISTICS OF CULTURED GREY MULLET (MUGIL CEPHALUS)—AN ANIMAL MODEL FOR PRESCREENING ANTIOXIDANT AND BLOOD THINNING ACTIVITIES

The sorghum distillery residue (SDR) has been an underutilized by‐product with estimated production of 150 ton/day in Kinmen, Taiwan. The objective of this study was to test for any physiological effects of SDR, thus to utilize it as a nutraceutical feed ingredient in diets for cultured fish. Hot air‐dried, wet, and dehulled‐wet sorghum distillery residue showed 63%, 90% and 97% inhibition of the hemoglobin‐catalyzed oxidation of linoleic acid compared to soybean (13%) and rice bran (78%). The feed formulated with 20% wet or dehulled‐wet sorghum distillery residue both showed an antioxidant activity of 68% being higher than the control diet (53%). Feeding these diets to cultured grey mullet for 60 days in summer (temperature ranged 24–30C), resulted in a lower hydroperoxide content in gill tissue, as shown by a chemiluminesence intensity of 1806 or 1409 mV as opposed to 2666 mV for fish fed a control diet. In winter, when the water temperature decreased to 14C, grey mullet fed a diet consisting of 10% dehulled wet sorghum distillery residue had a blood viscosity of 1.9 mPas and a hematocrit value of 33%, in contrast to 3.6 mPas and 41% for control. The blood of the control group started to aggregate in 6 h and showed hemolysis, while the mullet fed dehulled, wet sorghum distillery residue did not show blood aggregation, maintained normal fluidity and erythrocyte membrane integrity. It seems that cultured fish may have the potential as an animal model for prescreening antioxidant and blood thinning effects of food ingredients.     

BACK TO THE CITy: AN ANALySIS OF TRENDS IN THE SIXTIES AND SEVENTIES*

This study examines the ability of central cities within 61 large metropolitan areas to attract high status in-migrants and those in their most economically productive years. The emerging literature on central city revitalization suggests that the position of cities improved between the late fifties and late sixties, a pattern generally supported by the data. However, the data indicate that large northeastern and midwestern cities improved more rapidly than either smaller cities in the same region, or their large southern and western counterparts. These data suggest a kind of evolutionary sequence and support the hypothesis that the worst may indeed be over for northern central cities.     

BIOCHEMICAL AND MORPHOLOGICAL CHANGES IN GRASS SHRIMP (PENAEUS MONODON) MUSCLE FOLLOWING FREEZING BY AIR BLAST AND LIQUID NITROGEN METHODS

Grass shrimp (Penaeus monodon) at prerigor stage were frozen at rates ranging from 3.41 to 16.1 cm/h by using an air blast freezer at –35C or a liquid nitrogen freezer at – 80, – 100 and – 120C. Immediately after freezing, the spacing between muscle fiber bundles was larger (21.3 ± 5.7 μm) in shrimp frozen at 3.4 cm/h than in shrimp frozen at 8.6 ～ 16.1 cm/h (6.0 ± 0.6 to 8.8 ± 1.1 μm, respectively). The spacing between fibers increased during frozen storage at – 20C and remained different for slow and fast frozen samples within 4 weeks. The lysosomal fraction from fresh shrimp had more cathepsin D-like activity (187 units/mg protein) than that from shrimp frozen at 10.2 cm/h (179 units/mg protein) and at 3.4 cm/h (86 units/mg protein). During frozen storage at – 20C the cathepsin D-like activity of intact lysosomes decreased and was negligible after 4 weeks. The solubility of muscle protein in 0.6 M KCl was not consistently different in samples frozen by different methods and stored at – 20C for 4 weeks. Liquid nitrogen freezing produced frozen shrimp of higher muscle integrity than air blast. But the differences disappeared after one-month storage at – 20C.     

Odor intensity measured by an audio method

A nonverbal, nonnumerical method for measuring odor or taste intensity by means of cross-modal matching with pitch is described. The device with which the measurements are obtained is called an intensometer, and it allows subjects to simply react to intensity without having to describe or quantify what is perceived. The odor intensity function of benzaldehyde, an aromatic substance with a bitter almond odor, was obtained for individuals and for the panel by this method as well as by graphic scaling. A comparison of the two methods revealed better resolution and reliability with the intensometer, which showed no end effects or stimulus range bias.     

AMINO ACID COMPOSITION AND IN VITRO PROTEIN DIGESTIBILITY OF DRIED SQUID REHYDRATED IN WATER AND ALKALI

Crude protein content, amino acid composition and in vitro protein digestibility of fresh, dried and rehydrated Argentina squid (Illex argentinus) were studied. Most of the nonamino acid nitrogenous compounds in the mantle muscle dissolved in water during rehydration. Rehydration improved the nutritive value of protein in dried squid. Rehydration decreased the concentration of proline relative to total amino acids in muscle. Aromatic amino acids were limiting essential amino acids in fresh and dried squid but not in rehydrated squid. Amino acid scores increased with the extent of rehydration, more so in alkali than in water. The alkali rehydration also increased the in vitro protein digestibility of dried squid.     

Nonlinear modelling of periodic threshold autoregressions using Tsmars

We present new methods for modelling nonlinear threshold-type autoregressive behaviour in periodically correlated time series. The methods are illustrated using a series of average monthly flows of the Fraser River in British Columbia. Commonly used nonlinearity tests of the river flow data in each month indicate nonlinear behaviour in certain months. The periodic nonlinear correlation structure is modelled nonparametrically using TSMARS, a time series version of Friedman's extended multivariate adaptive regression splines (MARS) algorithm, which allows for categorical predictor variables. We discuss two methods of using the computational algorithm in TSMARS for modelling and fitting periodically correlated data. The first method applies the algorithm to data from each period separately. The second method models data from all periods simultaneously by incorporating an additional predictor variable to distinguish different behaviour in different periods, and allows for coalescing of data from periods with similar behaviour. The models obtained using TSMARS provide better short-term forecasts for the Fraser River data than a corresponding linear periodic AR model.     

Freezing tilapia by airblast and liquid nitrogen – freezing point and freezing rate

Processing data was obtained for the freezing of tilapia meat. The initial freezing point of tilapia meat was measured by differential scanning calorimetry (DSC), and also by measuring the centre temperatures of meat chunks during cooling. the freezing point was −1.03°C by DSC, and between −0.81 and −0.90°C by the cooling method, determined at the point where the standard deviation of the mean temperature was close to zero, i.e. a minimum.
Tilapia chunks, 0.95 to 1.45 cm thick, were frozen in an airblast freezer at −7, −20 and −36°C, and in a liquid nitrogen freezer at −87 and −128°C.
Freezing rate, defined as the half thickness of a meat chunk divided by the time for the centre temperature to decrease from 0 to −5°C, was 0.09 cmh⁻¹ at −7°C. At freezing temperatures of −20, −36, −87 and −128°C, the rates were respectively 4, 19, 158 and 331 times faster than that at −7°C, and correlated with freezing temperature ( r = 0.99) regardless of the freezing method.