Denise I. Skonberg

Nutrient composition of green crab (Carcinus maenus) leg meat and claw meat

Abstract Research is underway in New England to examine the potential for initiating a commercial fishery for the invasive European green crab ( Carcinus maenus ). Information on the nutrient composition is needed to facilitate the processing, utilization, and marketing of value-added green crab products. Green crabs were harvested and individually weighed and measured for carapace width. Claw meat and leg meat samples were picked from steamed crabs, and raw crabs were sampled for claw meat only. Samples were subjected to proximate, mineral (calcium, phosphorus, magnesium, sodium, potassium, aluminium, iron, zinc, copper), cholesterol, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) analyses. Moisture, protein, and total mineral contents of the crab meat averaged 78.7, 17.1, and 2.2 g/100 g, respectively. Leg meat had higher lipid concentrations (1.16 g/100 g) than either steamed (0.62 g/100 g) or raw (0.54 g/100 g) claw meat. Average n-3 fatty acid concentrations ranged from 115 to 336 mg/100 g and 154 to 344 mg/100 g for DHA and EPA, respectively, and were significantly higher in leg meat than in claw meat.

Gelation properties of previously cooked minced meat from Jonah crab (Cancer borealis) as affected by washing treatment and salt concentration

The influence of washing treatment (dewatered only, one wash, and three washes) and sodium chloride (NaCl) concentration (0%, 2%, and 4%) on the gelation properties of crab mince was investigated. This previously cooked muscle mince is a low-value by-product of the crab processing industry, considered to have little or no functional properties. Crab mince gels were produced and tested for water-holding capacity (WHC), gel strength, colour, and electrophoretic profile. Wash treatment and NaCl concentration significantly affected gelation. Washed samples exhibited significantly higher WHC than dewatered samples. The 4% NaCl treatment decreased WHC compared to lower NaCl levels. Multiple washing steps increased the force to gel deformation. Wash treatment and NaCl concentration also affected the colour of gels. Based on these results, cooked crab meat mince treated with three washes and 0% NaCl resulted in the strongest gels with the best water-holding capacity, which can be used in the development of value-added products.

Effect of Moisture Content and Screw Speed on the Physical Chemical Properties of an Extruded Crab-based Snack

Crab processing generates by-products that could be used in new value-added products to decrease processing waste and increase profits. In this product development study, the effects of moisture content and screw speed on physical properties and composition of an extruded crab-based snack product were investigated. Corn meal was fortified with 10% ground crab leg and passed through a twin-screw extruder using moisture contents of 25% and 30% and screw speeds of 200, 250 and 300rpm for a total of six treatments, extruded in duplicate. Screw speed and moisture content had a significant (p 0.05) influence on moisture content, expansion ratio, crunchiness and L-value of the extrudate while protein, fat, ash and mineral were not significantly (p 0.05) affected. As screw speed increased, moisture content and bulk density of the extrudates decreased. The snack product extruded at 25% moisture content and 300rpm had significantly different (p 0.05) physical properties compared to all other treatments. Increases in torque and melting temperature were observed for higher screw speed and lower extruding moisture content.

The Effectiveness of Ozone and Acidulant Treatments in Extending the Refrigerated Shelf Life of Fresh-Cut Potatoes

The objective of the study was to determine the effectiveness of acidulant dip treatments (with or without aqueous ozone) to reduce enzymatic browning and to extend the shelf life of fresh-cut potato slices during refrigerated storage (4 °C) for 28 d. Potato slices subjected to aqueous ozone (2 ppm) had significantly (P≤ 0.05) higher L-values and lower a-values, but ozone did not appear to have any effect on aerobic plate counts (APCs) or polyphenol oxidase (PPO) activity. NatureSeal (NS) and sodium acid sulfate (SAS) were the most effective acidulant treatments in reducing browning (significantly [P≤ 0.05] higher L-values, lower a-values, and browning index values) regardless of ozone treatment. NS and SAS also had lower PPO activity compared to other treatments on days 0 and 28, and significantly (P≤ 0.05) lower APCs (≤2.00 log CFU/g) over refrigerated storage. Therefore, the SAS treatment was comparable to NS, a commercially available product, and showed promise as an effective antibrowning dip to reduce browning and spoilage in fresh-cut potato products. Practical Application:  A 1% SAS dip treatment which included 1% citric and 1% ascorbic acid was found to be an effective antibrowning dip for fresh-cut potatoes along with NatureSeal®s PS-10, compared to other treatments. They were both effective in maintaining low microbial counts over refrigerated storage. Additionally, aqueous ozone washes (2 ppm) showed significant benefits to reduce browning; however, ozone did not affect microbial counts or PPO enzyme activity. Therefore, the SAS treatment could have potential use in the fruit and vegetable industry to reduce browning and spoilage in fresh-cut potato products.

Oxidative stability and consumer acceptance of fish oil fortified nutrition bars.

UNLABELLED Oat and soy-based nutrition bars were fortified with 4 levels of fish oil (0, 6, 12, or 18 g per approximately 600 g batch), representing 0%, 20%, 40%, or 60% replacement of canola oil. The commercially available purified fish oil was not emulsified nor encapsulated, and contained tocopherols. Baked nutrition bars were evaluated for proximate composition, water activity, alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic (DHA) content, and consumer acceptance using a 9-point hedonic scale. The bars were sealed in opaque bags and stored in a stability chamber at 25 °C and 50% relative humidity for 10 wk to assess oxidative stability. There were no significant (P > 0.05) differences in proximate composition, water activity, or ALA levels among treatments. EPA and DHA levels were significantly (P < 0.05) different among treatments, averaging 178.1 mg/serving (20-FO), 488.3 mg/serving (40-FO), and 664.6 mg/serving (60-FO), but none changed during storage. Headspace hexanal and propanal levels decreased over time but were not significantly different among treatments until week 10. Peroxide values were not significantly different except between the control and 60-FO bars. Low values obtained for these analyses suggest negligible oxidation in the bars. Consumer acceptance scores did not differ significantly between the control and lowest fortification level (20-FO), ranging from 6.4 to 6.6 for aroma, texture, flavor, and overall acceptability. These results suggest that nonemulsified, nonencapsulated fish oil can successfully replace canola oil in intermediate moisture nutrition bars to provide EPA and DHA levels as high as 178 mg/serving without affecting consumer acceptability or oxidative stability. PRACTICAL APPLICATION Omega-3 fatty acid rich fish oil has been shown to have numerous health benefits, but there are limitations to its use in shelf-stable food products. In this study, nutrition bars were successfully fortified with nonencapsulated, nonemulsified fish oil to deliver 178 mg EPA and DHA per 35 g serving. The fortified bars were oxidatively stable over 10 wk and acceptable to consumers.

Impact of post-rigor high pressure processing on the physicochemical and microbial shelf-life of cultured red abalone (Haliotis rufescens).

High pressure processing (HPP) of post-rigor abalone at 300MPa for 10min extended the refrigerated shelf-life to four times that of unprocessed controls. Shucked abalone meats were processed at 100 or 300MPa for 5 or 10min, and stored at 2°C for 35days. Treatments were analyzed for aerobic plate count (APC), total volatile base nitrogen (TVBN), K-value, biogenic amines, color, and texture. APC did not exceed 10(6) and TVBN levels remained below 35mg/100g for 35days for the 300MPa treatments. No biogenic amines were detected in the 300MPa treatments, but putrescine and cadaverine were detected in the control and 100MPa treatments. Color and texture were not affected by HPP or storage time. These results indicate that post-rigor processing at 300MPa for 10min can significantly increase refrigerated shelf-life of abalone without affecting chemical or physical quality characteristics important to consumers.

Antioxidant Properties of Chitosan Coatings on Frozen Atlantic Salmon Fillet Portions

Atlantic salmon contain omega-3 fatty acids, which play important roles in promoting human health but are highly susceptible to oxidation. Chitosan has been shown to have antioxidant properties which could be beneficial in extending the shelf life of Atlantic salmon; however, the effects of chitosan molecular size on oxidation of salmon fillets have not been reported. The primary objective of this study was to evaluate the effects of chitosan coatings on lipid oxidation of Atlantic salmon fillet portions during 5 months frozen storage. The effects of chitosan molecular weight (high molecular weight, low molecular weight, and enzymatically degraded chitosan), concentration (0.5 and 1.0%), and the addition of 1% ascorbic acid to the chitosan coating were evaluated. Chitosan molecular weight significantly affected oxidation as evaluated by propanal levels and changes in L* values of the fillet portions. The chitosan treatment with added ascorbic acid resulted in the lowest propanal levels during 5 months of frozen storage. Manipulation of chitosan molecular weight and incorporation of natural antioxidants into chitosan coatings can provide an effective method of reducing lipid oxidation during extended frozen storage of seafood products.

Effects of Rigor Status during High‐Pressure Processing on the Physical Qualities of Farm‐Raised Abalone (Haliotis rufescens)

High-pressure processing (HPP) is used to increase meat safety and shelf-life, with conflicting quality effects depending on rigor status during HPP. In the seafood industry, HPP is used to shuck and pasteurize oysters, but its use on abalones has only been minimally evaluated and the effect of rigor status during HPP on abalone quality has not been reported. Farm-raised abalones (Haliotis rufescens) were divided into 12 HPP treatments and 1 unprocessed control treatment. Treatments were processed pre-rigor or post-rigor at 2 pressures (100 and 300 MPa) and 3 processing times (1, 3, and 5 min). The control was analyzed post-rigor. Uniform plugs were cut from adductor and foot meat for texture profile analysis, shear force, and color analysis. Subsamples were used for scanning electron microscopy of muscle ultrastructure. Texture profile analysis revealed that post-rigor processed abalone was significantly (P < 0.05) less firm and chewy than pre-rigor processed irrespective of muscle type, processing time, or pressure. L values increased with pressure to 68.9 at 300 MPa for pre-rigor processed foot, 73.8 for post-rigor processed foot, 90.9 for pre-rigor processed adductor, and 89.0 for post-rigor processed adductor. Scanning electron microscopy images showed fraying of collagen fibers in processed adductor, but did not show pressure-induced compaction of the foot myofibrils. Post-rigor processed abalone meat was more tender than pre-rigor processed meat, and post-rigor processed foot meat was lighter in color than pre-rigor processed foot meat, suggesting that waiting for rigor to resolve prior to processing abalones may improve consumer perceptions of quality and market value.

Mechanical Separation of Green Crab (Carcinus maenas) Meat and Consumer Acceptability of a Value-Added Food Product

ABSTRACT Mechanical separation of green crab resulted in an average mince yield of 49.2%, with average moisture, ash, protein, and lipid contents of 81.0, 5.1, 10.4, and 1.4%, respectively. Mince from small crabs (< 55-mm carapace width) had significantly lower lipid contents and L* values than mince from large crabs (> 55 mm). The overall acceptability of green crab mince empanadas (fried, stuffed pastries) was rated between “like slightly” and “like moderately” by a consumer panel (n = 87), regardless of empanada formulation (30, 50, or 70% mince by filling weight). Additionally, 63% of respondents indicated they would “probably” or “definitely” buy the empanadas if available locally.

Quality evaluation of American lobsters fed diets containing crab processing waste

Abstract The objectives of this study were to evaluate the effects of incorporating wet crab processing waste (CW) into pelleted feeds on (1) weight gain; (2) shell strength; (3) sensory quality; and (4) proximate composition of American lobsters. Soft shell lobsters were fed one of three pelleted diets (0%, 20% or 40% CW) or a cod rack control (industry standard diet) for 6 weeks. Lobsters fed the 40CW diet had similar weight gains to those fed the control diet. Lobsters fed the CW diets had higher concentrations of shell ash and calcium compared to the controls, however, lobsters from the control treatment had significantly stronger shells as measured by compression to fracture. Sensory analyses revealed no adverse affect of the 40% CW diet on texture or flavor of tail meat. Protein and lipid composition of lobster tail meat was not significantly affected by dietary treatment.