EFFECT OF CHLORINATED WASH WATER ON QUALITY OF HEAT SHOCKED MUSSEL MEAT

Chlorine-assisted chilled tumble washing of green mussel meats was done using 5 and 10ppm chlorine solutions maintained at 5 and 10C for 3 min. No significant difference (P < 0.05) was established in terms of meat yield, pH, Aw or sensory qualities for tumble washed samples. The mussel meats were given sensory acceptance ratings of up to "like slightly". A 2% weight gain of mussel meats was established after washing. Heat shocking in tandem with tumble washing affected 1–3 unit log reduction in TPC and coliform counts and about a 4 log reduction in Vibrio spp. counts of mussel meats. The 2 protocols were presented as value-adding steps to improve mussel meat quality. Philippine micro- and small-scale shellfish processors and vendors were identified as potential users of the technology presented in the study.     

TESSA—A new greedy heuristic for facilities layout planning

TESSA is a heuristic for determining which facilities should be adjacent in a planar layout. Once the adjacencies are known the block plan can be constructed by existing techniques. TESSA overcomes problems with earlier heuristics for determining adjacencies as it does not require planarity testing nor does it restrict the type of layout produced. The algorithm is polynomial in time and produces good quality solutions, almost all of which are above 90% of the (often unattainable) upper bound.     

OXIDATIVE STABILITY OF FRESH AND HEAT-PROCESSED DARK AND LIGHT MUSCLES OF MACKEREL (Scomber scombrus)

Oxidative stability of light and dark comminuted muscle of raw and thermally processed mackerel stored at 4C was studied over a 21 day period by monitoring changes in conjugated dienes (CD) and 2-thiobarbituric acid (TBA) values. The quantity of headspace (HS) volatiles, propanal, and hexanal as well as the ratio of aliphatic to olefinic (R_ao) or diallylmethylene (R_ad) protons in the proton nuclear magnetic resonance (¹ NMR) spectra of oils were determined. The content of CD of light and dark ground mackerel muscle samples exhibited a consistent increase over the entire storage period. Furthermore, secondary oxidation products as reflected in the TBA values and content of propanal, hexanal and HS gases, generally, showed a gradual increase in their level. The concentration of propanal, the dominant volatile of the HS gases, increased markedly up to day 6 of storage, but afterwards began to decline continuously. A similar trend was noted for hexanal, but at a lesser extent. The R_ao and R_ad values in the ¹H NMR spectra of lipids from all stored samples increased constantly during storage. In all samples, the dark ground muscle exhibited a higher degree of oxidation than its light counterpart. Furthermore, heat-processed dark comminuted muscle oxidized faster than its raw counterpart while generally an opposite trend was observed for the light ground muscle.     

Phosphorus detection in vitrified bacteria by cryo‐STEM annular dark‐field analysis

Bacterial cells often contain dense granules. Among these, polyphosphate bodies (PPBs) store inorganic phosphate for a variety of essential functions. Identification of PPBs has until now been accomplished by analytical methods that required drying or chemically fixing the cells. These methods entail large electron doses that are incompatible with low‐dose imaging of cryogenic specimens. We show here that Scanning Transmission Electron Microscopy (STEM) of fully hydrated, intact, vitrified bacteria provides a simple means for mapping of phosphorus‐containing dense granules based on quantitative sensitivity of the electron scattering to atomic number. A coarse resolution of the scattering angles distinguishes phosphorus from the abundant lighter atoms: carbon, nitrogen and oxygen. The theoretical basis is similar to Z contrast of materials science. EDX provides a positive identification of phosphorus, but importantly, the method need not involve a more severe electron dose than that required for imaging. The approach should prove useful in general for mapping of heavy elements in cryopreserved specimens when the element identity is known from the biological context.     

VARIED ASSAYS FOR PSP TOXINS IN HEAT SHOCKED PHILIPPINE GREEN MUSSELS (PERNA VIRIDIS)

Toxin assays namely: the mouse bioassay, the receptor binding assay (RBA) and, the immuno-chromatography assay using MIST Alert™ rapid test kit were used to determine the concentrations of Paralytic Shellfish Poisoning (PSP) toxins from untreated and heat shocked Philippine green mussels, Perna viridis contaminated with Pyrodinium bahamense var. compressum. Toxin levels ranging from 4–15 μg STXeq/100 g sample were quantified in the mussel samples analyzed using RBA. Higher levels of PSP toxins at about 30 μg STX eq/100 g sample were recorded using mouse bioassay, which was attributed to interfering factors that could induce mouse death resulting in false positive reactions. The MIST Alert™ test kit showed positive reaction in the samples evaluated based on the reported average profile of PSP toxin analogues at about 40 μg STX eq/100 g sample. The test heat treatments did not elicit definitive change in the PSP toxin profiles of heat shocked mussels relative to the untreated samples.     

MULTIFACTORIAL STUDY OF HAZE FORMATION IN MODEL WINE SYSTEMS

A multifactorial design was used to study the role of protein (Pro), polyphenols (PP), sucrose (Suc), pectin (Pec), potassium (K), and pH in the formation of haze in wine. Model wines (32) containing two levels of each factor plus yeast and nutrients were made and allowed to ferment to 0 Brix. Measurements of transmission at 633 nm (%T) following heating showed that PP, Pro, Pro*PP, Pec, and PP*Pec were all significant factors affecting turbidity. Molecular weight and size determinations by size‐exclusion chromatography‐laser light scattering indicated that molecular weight depended on Suc*Pec, Pro*PP*pH, and Pro*Pec*pH while molecular radius depended on PP*Suc*Pec, Pro, PP*Pec, and Suc*pH. Measurement of protein after filtration showed that Pro, PP, Pro*PP, and Pro*PP*pH were all factors. Laser diffraction studies showed three primary peaks in the range 0.05 ‐ 800 μm. The smallest size range had Pro*pH as a significant factor, while the largest had Pec and Pro*K as factors. These results indicate that a variety of factors are important to haze formation and that measurement of particle size, distribution, and interactions depends upon the instrument used to measure it.     

Consumer Acceptability and Color of Deep-Fried Fish Coated with Wheat or Corn Distillers'Dried Grains with Solubles (DDGS)

Distillers’dried grains with solubles (DDGS) from hard red wheat, soft white wheat and corn were used at a substitution level of 25% by weight for all-purpose flour in a conventional batter mix for fried fish. Fried fish nuggets (Alaskan pollock) prepared with a 25% DDGS batter either with or without a Japanese-style Panko breading were evaluated by a consumer panel (N = 2,546) for acceptability. All experimental products were rated as acceptable. There were no significant differences among the ratings of the products coated with batter only. However, products coated with batter and then with Panko breading were rated differently: the corn DDGS coated sample was rated higher than the control, while the white and red wheat DDGS coated samples received the lowest ratings. International color measurements of the dry batter mixes and the fried fish nuggets containing DDGS were darker than the controls.     

QUALITY CURVES FOR MANGO FRUIT (CV. TOMMY ATKINS AND PALMER) STORED AT CHILLING AND NONCHILLING TEMPERATURES

“Tommy Atkins” and “Palmer” mangoes were harvested medium‐ripe held for 7–20 days at five different temperatures and evaluated for quality attributes. The objective of this work was to obtain quality curves at chilling and nonchilling temperatures and to identify, for each temperature, which quality factors limit mango marketability. Chilling injury and increased fruit softness were the limiting quality factors for mango stored at 2 and 5C. Softening of the fruit, changes in color and development of decay were the limiting quality factors for mango stored at 12, 15 and 20C. Prediction of mango shelf life calculated from the data reported in the literature is not precise unless the characteristics of the fruit and environmental factors involved are well known. The curves obtained from quality evaluations for each temperature showed that a single quality attribute cannot be used to express loss of quality of mango over the normal physiological range of temperatures.