Development of Botulinal Toxin and Sensory Deterioration During Storage of Vacuum and Modified Atmosphere Packaged Fish Fillets

Toxin production by C. botulinum type E was studied in cod, whiting, and flounder filets packaged in air-permeable film, vacuum packages and packages flushed with N₂ or CO₂ during storage at 8°, 12° or 26°C. Cod and whiting filets were flushed with CO₂ and stored continuously at 4°C or cycled between 4° or 8° and 26°C. Cod and whiting fillets were flushed with gas mixtures and stored at 8°C or 26°C. Flounder deteriorated rapidly and was rejected by sensory evaluation prior to toxin detection during vacuum or modified atmosphere storage at 12°C and 8°C but after toxin detection at 26°C. Toxin was present either prior to or simultaneously with sensory rejection of cod and whiting fillets for all vacuum or modified atmosphere treatments and temperature regimens.     

Muscle Washing and Raw Material Source Affect Quality and Physicochemical Properties of Low-salt, Low-fat, Restructured Beef

Five percent unwashed and washed skeletal (USM and WSM) and cardiac (UCM and WCM) muscle and fish surimi (FS) were evaluated in precooked (64.4 °C), restructured beef using 0.2% NaCl. Additionally, a 0.2% NaCl product without binder and a 1.0% NaCl treatment containing 5% USM were made. Washing enhanced sensory and instrumental texture measures of products containing CM but did not affect products containing SM. UCM and WCM appeared beneficial for maintenance of product color but tended to increase lipid oxidation. Washing reduced surface hydrophobicity, decreased disulfide content of CM, increased free sulfhydryls of CM and SM, and lowered soluble protein in binder extracts. Binders did not improve product characteristics.     

Study of the White Film Developed on the Cut Surface of Vacuum-packed Dry-cured Ham Slices

Scanning electron microscopy of the white film developed on the cut surface of some vacuum-packed dry-cured ham slices showed a fibrous structure composed of protein materials. Gradient SDS-PAGE revealed the main components in the film were proteins with molecular weight in the range 26000–87000, but especially 37000, 41000, 56000, and 65000. Free amino acids were also in the film in low proportions (250 μg total free amino acids per mg of protein). The main amino acids were proline methionine, isoleucine, leucine, phenylalanine, histidine and tyrosine. 11.7% of the total free amino acids was tyrosine, thus indicating its minor role in formation of white film.     

Flaked Sinew Addition to Low-fat Cooked Salami

Flaked sinew (FS) was added at three levels (7.5, 15, and 22.5%) to low-fat, 20% added water (AW) salamis. A 1.27 cm Comitrol machine head was used to produce large (flaked once) and small (flaked twice) particle sizes. Treatments were preblended (P) and non-preblended (N). P and N controls contained 10% and 20% fat, respectively. Addition of FS decreased (P < 0.05) moisture compared to controls. Yields decreased (P < 0.05) as FS increased regardless of particle size; however, FS addition minimized purge. Lightness increased (P < 0.05) as FS increased in N treatments compared to the low-fat control. Break force/cm² increased (P < 0.05) in P controls compared to N controls. Large FS particle size N treatments had higher (P < 0.05) peak force values than those with small particle size. FS treatments were comparable to high-fat controls in palatability traits.     

Efficiency of Removing Volatiles from Menhaden Oils by Refining, Bleaching, and Deodorization

Atlantic and Gulf of Mexico menhaden (Brevoortia spp) oils from refining, bleaching and deodorizing steps were analyzed for volatile components by combined techniques of dynamic headspace sampling, high resolution gas chromatography and mass spectrometry. Results indicated that alkali-refining and clay-bleaching removed many odorous short-chain oxygenated compounds and alkylbenzenes; steam-deodorization (200–208°C, 3 hr) eliminated most volatiles. Some volatiles in deodorized samples were attributed to container material and antioxidants.     

Calcium Oxalate Crystals: The Irritant Factor in Kiwifruit

The cause of irritation in the mouth, when kiwifruit nectars and dried kiwifruit products are ingested, was investigated. Idioblast cells that contain raphide crystals of calcium oxalate were isolated from inner pericarp tissue of the fruit and studied by light and electron microscopy. An experienced panel of 9 judges detected an irritation from sweetened apple puree when isolated raphide crystals were incorporated at the rate of 30 mg oxalate/100g of puree. Sensory and microscopic studies showed evidence that the irritation was caused by sharp calcium oxalate crystals exposed during processing.     

Static Fatigue of Optical Fibers in Bending

A two-point bending technique for making static fatigue measurements on optical fibers is described which allows large quantities of data to be rapidly and conveniently gathered. Statistical analysis is used to compare the times to failure of the method with those of the commonly used mandrel and tensile methods. Direct experimental comparison of the two-point bend and tensile methods shows that while the times to failure are generally longer for two-point bend than tension, the essential fatigue behavior is identical for the two methods.     

EFFECTS OF PROCESSING ON ADSORPTION OF OFF-FLAVORS ONTO SOY PROTEIN1

Heats of adsorption and adsorption coefficients for the reversible adsorption of several aliphatic alcohols, aldehydes, and ketones on soy protein were measured using gas chromatography. The physical state of protein samples was changed by heating at 100°C and 121°C at moisture contents of 29%and 40%. A comparison was made with values for untreated soy isolate and sheared soy isolate, and the effects of moisture, temperature, and their interaction were examined by analysis of variance. Heats of adsorption were unchanged, but changes in adsorption coefficients of the treated samples demonstrated a significant decrease in binding that can be attributed to protein denaturation. The response depended on the interaction of moisture and temperature effects.     

Aluminum Oxyhydroxides Formed by the Reaction of Methyl Esters with Sodium Aluminate Solution

Properties of the aluminum oxyhydroxide formed by the reaction of methyl acetate on solutions of sodium aluminate are examined. The solid has a high specific surface and gives an X-ray diffraction pattern different from those of other known oxyhydroxides. A quite different product (coarse bayerite) is obtained when esters which cannot have an enolic form are used. A possible formation mechanism of the oxyhydroxide is discussed.