Gamma-Irradiation of Frozen Kiwifruit Pulp

Frozen (–18°C) de-seeded kiwifruit pulp (Actinidia deliciosa) was irradiated at a dose of 100 krad and stored at -18°C. Irradiation resulted in a 2.11 log₁₀ reduction in aerobic plate count (APC) with bacteria being most susceptible. Molds were less susceptible than yeasts. Assessments carried out over 6 months storage showed no significant differences in physical, chemical and sensory properties between irradiated and nonirradiated pulps. The microbial populations of the pulps decreased in parallel throughout the storage period. Frozen storage without irradiation resulted in a 3 log₁₀ reduction in APC over the 6 months period, a 38% reduction in ascorbic acid, and a slight loss of color. Three days frozen storage (– 18°C) following irradiation resulted in an APC only 0.89 log₁₀ higher than 6 months frozen storage (- 18°C) without irradiation with potential savings in energy and holding times which could have economic benefits.     

Phase Equilibria in the System CaO-MgO-B2O3 at 900°C

Phase equilibria in the system CaO-MgO-B₂O₃ were investigated at 900°C using X-ray powder diffraction techniques. With the exception of MgO-B₂O₃, the binary phases reported previously were confirmed, but no ternary phases were found. Solid solution effects were investigated for the binary phases by comparison of patterns, whereas for CaO and MgO, accurate lattice parameters were compared. No solid solutions were detected. As a result, the isothermal equilibrium diagram at 900°C reduces to three phase triangles. X-ray powder diffraction data for the calcium berates are included.     

Response of American consumers to akara, a traditional West African food made from cowpea paste

Dry cowpeas, an excellent source of protein and B-vitamins, are underutilized in the US primarily because of their inconvenience. Akara, a popular West African food made from whipped cowpea paste that is seasoned and deep-fat fried, has potential for extending use of cowpeas in US markets. Acceptance tests involving 450 respondents were conducted to assess response of US consumers to akara. Akara was most acceptable to Caucasians, older consumers, and those with no, little or some high school education. Its most appropriate use was perceived as a snack food with sauce and as a fully cooked, frozen, reheatable product.     

A quantitative model for predicting the morphology of surface initiated rolling contact fatigue cracks in back-up roll steels

ABSTRACT A previously presented qualitative model for the rolling contact fatigue and spalling failure of back‐up rolls has been quantified in terms of crack lengths and growth directions. The morphologies of surface initiated fatigue cracks have been predicted using published data on the mode I and mode II thresholds in low carbon and roll steels, respectively, and the theoretical determination of the mode I and mode II stress intensity factors at the tips of the inclined surface cracks. The predictions have been validated by using the results of the metallographic examination of rolling contact fatigue cracks produced in test discs used in experimental simulations and the examination of spalled material from a back‐up roll.     

Spoilage of Rested Harvested King Salmon (Oncorhynchus tshawytscha)

ABSTRACT Laboratory-reared king salmon were harvested using CO₂ anesthetizing (CO₂) or by rested harvesting techniques using AQUI-S(tm) anesthetizing (AQUI-S). Fish were killed by spiking, and flesh portions were stored in air packs (0°C) for 22 d. Headspace oxygen levels, sensory characteristics (raw and cooked), tensile properties, drip loss, gaping, pH, nucleotide derivatives, color, and bacterial counts were determined after 5 to 22 d of storage. All parameters except tensile properties showed significant trends with storage time. Oxygen levels were consistently lower in CO₂ packs whereas, on average, drip was lower in AQUI-S samples, and L*-values and bacterial numbers were higher in AQUI-S samples. Overall, harvesting effects had minimal impact on the quality parameters measured.     

Image analysis to reveal crack development using a computer simulation of wear and rolling contact fatigue

Plastic flow of near‐surface rail material under contact loading is a feature of rail–wheel contact, and severe flow typically leads to both wear, and the initiation and development of small surface‐breaking cracks. This paper presents results from a ratcheting based computer simulation, which has been developed to allow the simultaneous investigation of wear, crack initiation and early crack propagation. To identify repeatably small crack‐like flaws, image analysis is applied to the visual representation of the wearing surface generated by the model. This representation shows a good similarity to traditional micrographs taken from sections of worn surfaces. The model clearly reveals the interaction of wear with crack development, processes which are linked because wear truncates surface‐breaking cracks, and can completely remove small surface‐breaking cracks.     

EFFECTS OF ELECTRICAL STUNNING DURATION ON POSTMORTEM RIGOR DEVELOPMENT AND BROILER BREAST MEAT TENDERNESS

Experiments were conducted to determine the effect of electrical stunning duration on poultry breast meat postmortem biochemistry and texture. Broilers were stunned with 100 V AC for 0, 5, 10, 20, or 40 s, killed by conventional neck cut, and bled for 180 s to determine percentage blood loss. Breast fillets were removed from the carcass immediately after picking or following 24 h of aging in an ice-water bath. R-values and pH were determined at both deboning times and Allo-Kramer shear values were recorded after holding the samples for 48 h at 2 C. Stunning durations of 10, 20 and 40 s resulted in lower (P < 0.05) blood losses than birds stunned for 0 or 5 s. Stunning inhibited postmortem glycolysis as indicated by higher (P < 0.05) pH values and lower R-values at 15 min postmortem, but not after 24 h. Stunning had no effect on Allo-Kramer shear values. Stunning durations from 5 to 40 s at 100 V AC had no significant effect on postmortem rigor development, or meat quality.     

Shelf-life of Sterile Yellow-eyed Mullet (Aldrichetta forsteri) at 4°C

The relative effects of microbial and nonmicrobial spoilage on the shelf-life of yellow-eyed mullet were studied. Results of sensory and chemical analyses of sterile flesh stored at 4°C were compared with fillets which had either spoiled naturally while held at 4°C or frozen fillets held at ?18°C. Inosine was produced rapidly in both treatments at 4°C, followed in sterile flesh by a slower breakdown to hypoxan-thine. Hypoxanthine production from inosine was rapid in the presence of bacteria. Within 6 days sensory changes were observed in the frozen flesh and after 69 days, it was considered unacceptable. The development of off-odors and off-flavors in the absence of bacteria was not sufficiently slow to result in a significant extension in shelf-life for this species.     

Design and Construction of an Ion-Exchange Denitrification Plant in South Staffordshire

Increasing concern about rising levels of nitrate in groundwater supplies and their subsequent removal to comply with EC drinking water standards has led to the construction of the first full-scale ion-exchange nitrate-removal plant in the UK by the South Staffordshire Waterworks Company.
This paper describes the development of the project from concept, through pilot-plant studies to final design, installation and commissioning. It explains the role of ion-exchange technologies, the use of recently developed nitrate-selective resins and the development of a novel dual regeneration system. The initial performance of the full-scale plant is discussed.