Brian Perkins

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.

Determination of capsinoids by HPLC-DAD in Capsicum species.

Capsicum fruits contain a newly discovered phytochemical called capsinoids. Because little is known about the quantities of these compounds in both sweet and pungent pepper fruits, a high-performance liquid chromatography (HPLC) method was developed to identify and quantify the capsinoids (naturally present E-capsiate and dihydrocapsiate) utilizing fruit obtained from a variety of Capsicum spp. in the U.S. Department of Agricultures Capsicum germplasm collection. Capsinoids were extracted with acetonitrile, filtered, and analyzed using an HPLC system equipped with a C(18) monolithic column, gradient pump, and diode array detector. The elution solvents were acetonitrile and water (60:40) with an isocratic flow rate of 1.0 mL/min. Forty-nine samples representing distinct morphotypes of four cultivated species ( C. annuum var. annuum, C. annuum var. glabriusculum, C. baccatum , C. chinense , and C. frutescens ) contained detectable levels (11-369 microg/g) of E-capsiate quantified at a wavelength of 280 nm. Nine of the E-capsiate-containing samples also had dihydrocapsiate (18-86 micro/g). Gas chromatography with a mass spectrometry detector (GC-MS) confirmed the presence of these compounds in the Capsicum spp.

Sensory and fatty acid analyses of two Atlantic species of Porphyra (Rhodophyta)

Sensory analyses were conducted to determine levels of consumer acceptability of Porphyra yezoensis, P. umbilicalis, and P. amplissima to select appropriate species for aquaculture development in Maine (USA). The subjects included children (n = 67) and adults (n = 84); the children participated in study design by helping to select the 9 point hedonic scale used in the affective sensory tests. Two substrates were used; Porphyra was baked in crackers and also used as a coating for popcorn. No significant differences (p > 0.5) in acceptability of one species over another were observed in either trial, which suggests that native Atlantic species of Porphyra such as P. amplissima and P. umbilicalis have developmental potential in foods for North American consumers. Fatty acids were analyzed in the taste test material and in freshly collected P. umbilicalis; eicosapentaenoic acid [EPA; 20:5 (n-3)] and palmitic acid were the most common fatty acids. Quantitative analysis of EPA determined that freshly collected (January 2005) P. umbilicalis contained 3.2 mg EPA g dry wt−1 (74 mg EPA 100 g fresh wt−1). This concentration is not high enough to make P. umbilicalis a primary source of daily omega-3 fatty acids, but the favorable n-3/n-6 ratio (2-3:1) in these species contributes to their nutritional value.

Spectroscopic Analysis of Hemolymph from the American Lobster (Homarus americanus)

ABSTRACT Hemolymph from the American lobster (Homarus americanus) was analyzed by optical spectroscopy for the concentration of total hemolymph proteins and results were compared with a more traditional technique: refractometry. Absorbance peaks at 280 nm for total hemolymph protein concentration and 334 nm for hemocyanin concentration were studied, compared with equivalent refractometry readings, and correlated to the vitality of the lobster. These spectroscopic measurements constitute engineering data in the design a future noninvasive, field-deployable microinstrument to sort lobster according to their health and long-term viability.

Determination of thiabendazole in potatoes by ELISA

A method was developed to analyze thiabendazole (TBZ) in potatoes. Potatoes were extracted in methanol for 3 min with a polytron. A 100‐l aliquot was removed and evaporated to dryness using air. The residue was dissolved in 1 ml of high‐performance liquid chromatography (HPLC) grade water before quantifying TBZ using an existing antibody with a tube‐formatted competitive enzyme‐linked immunosorbent assay (ELISA). Eight samples could be analyzed in 25 min without the use of complex and expensive equipment. Indeed, samples could be analyzed at storage facilities. The detection limit for this assay in potatoes was 3 ppb. Reproducibility and accuracy were good. Correlation of TBZ concentration between HPLC and ELISA was 0.9729 for 78 samples.

Analytical and Semipreparative HPLC Analysis and Isolation of Hemocyanin from the American Lobster Homarus americanus

ABSTRACT Hemocyanin, which has numerous research and commercial biotechnology applications, is currently available from just two sources: the keyhole limpet and the horseshoe crab. Obtaining and purifying hemocyanin from these sources is a complex but necessary process because this compound cannot be synthesized in the laboratory. Lobster hemolymph, an abundant by-product of the lobster meat processing industry, could be developed as a new source of hemocyanin. A reliable and inexpensive method of extracting hemocyanin from lobster hemolymph would increase hemocyanin supplies through development of a value-added product from processing waste. Currently, ultracentrifugation is the most common commercial method of purifying hemocyanin. This technique, which requires several days of processing time, is not a reliable method of separating hemocyanin oligomers. We report new separation and purification techniques based on size-exclusion high-performance liquid chromatography, and methods of determining the quantitative and qualitative properties of hemocyanin derived from lobster hemolymph. In addition, an analytical and semipreparative method was developed to separate and purify hexamers and dodecamers from American lobster hemolymph. The shelf-life of hemocyanin hexamers and dodecamers extracted using the newly developed methods was determined to be more than 30 days with no observed degradation of the hemocyanin oligomers.