Alexandra C. M. Oliveira

Purification and characterization of pepsin-solubilized collagen from skin and connective tissue of giant red sea cucumber (Parastichopus californicus).

Pepsin-solubilized collagen (PSC) was extracted from giant red sea cucumbers ( Parastichopus californicus ) and characterized for denaturation temperature (T(d)), maximum transition temperature (T(m)), enzyme-digested peptide maps, and gel-forming capability. SDS-PAGE showed that PSCs from giant red sea cucumber skin and connective tissue were both type I collagens, consisting of three alpha(1) chains of approximately 138 kDa each. The amino acid composition and peptide maps of PSCs digested by V8 protease were different from those of calf skin type I collagen. The T(d) and T(m) are 18.5 and 33.2 degrees C, respectively, for skin PSC and are 17.9 and 32.7 degrees C, respectively, for connective tissue PSC. Both skin and connective tissue PSCs exhibited good gel-forming capability at pH 6.5 and at an ionic strength of 300 mM salt (NaCl). Collagen isolated from giant red sea cucumbers might be used as an alternative to mammalian collagen in the food and pharmaceutical industries.

Lipid Composition of Alaska Pink Salmon (Oncorhynchus gorbuscha) and Alaska Walleye Pollock (Theragra chalcogramma) Byproducts

ABSTRACT In Alaska, over one million metric tons (MT) per year of fish processing byproducts are produced. The objective of this study was to determine the fatty acid profile and quantitate lipid classes in the extracted oils of byproducts from pollock (heads, frames, viscera, skins) and salmon (heads, viscera). In pollock, viscera had the highest percent lipid and in salmon, heads had the highest lipid content. All fish parts from both salmon and pollock were rich in omega-3 fatty acids, which ranged from 25% to 36% in the extracted oils. Differences among byproducts in fatty acid content and percent of lipid classes were detected in both salmon and pollock.

Chemical composition of the giant red sea cucumber, Parastichopus californicus, commercially harvested in Alaska

Giant red sea cucumbers, Parastichopus californicus, are commercially harvested in the U.S. Pacific Northwest; however, the nutritional and chemical properties of its edible muscle bands and body wall have not been fully elucidated. In particular are the fatty acid profiles of P. californicus tissues, which have not been documented. Sea cucumbers were delivered live and muscle bands and body wall freeze dried, vacuum packed, and stored at –30°C until analyzed. Proximate composition of freeze-dried tissues varied greatly with muscle bands being composed of 68% protein, 12% ash, 9% carbohydrate, and 5% lipids, while the body wall was composed of 47% protein, 26% ash, 15% carbohydrate, and 8% lipids. The hydroxyproline, proline, and glycine contents of the body wall were much higher than those in muscle bands, consistent with the larger amount of connective tissue. Calcium, magnesium, sodium, and iron contents were higher in the body wall than those in muscle bands, whereas the opposite was observed for zinc content. Total long-chain n-3 fatty acid contents were 19% and 32% of total fatty acids in body wall and muscle bands, respectively. Muscle bands had higher content of eicosapentaenoic acid (20:5n-3) than body wall at 22.6% and 12.3%, respectively. High content of arachidonic acid (20:4n-6) was recorded in both body wall (7.1%) and muscle bands (9.9%). Overall, the fatty acid profiles of body wall and muscle bands of P. californicus resemble those described for other species; however, the distribution and occurrence of certain fatty acids is unique to P. californicus, being representative of the fatty acid composition of temperate-polar marine organisms. The chemical characterization of freeze-dried edible tissues from P. californicus demonstrated that these products have valuable nutritional properties. The body wall, a food product of lower market value than muscle bands, could be better utilized for nutraceutical and pharmaceutical applications.

Chemical characterization of commercial liquid smoke products

The objective of this study was to determine important chemical characteristics of a full-strength liquid smoke, Code 10-Poly, and three refined liquid smoke products (AM-3, AM-10 and 1291) commercially available (Kerry Ingredients and Flavors, Monterey, TN). The pH of the products were significantly different (P < 0.05) and ranged from 2.3 (Code 10-Poly) to 5.7 (1291). The pH was inversely correlated with titratable acidity (R2 = 0.87), which was significantly different (P < 0.05) among products ranging from 10.3% acetic acid (Code 10-Poly) to 0.7% acetic acid (1291). Total phenol content was quantified using the Gibbs reaction; the only liquid smoke containing appreciable level of phenolic compounds was Code 10-Poly at 3.22 mg mL−1. Gas chromatography-mass spectrometry (GC-MS) analysis of liquid smoke dichloromethane extracts revealed that carbonyl-containing compounds were major constituents of all products, in which 1-hydroxy-2-butanone, 2(5H)-furanone, propanal and cyclopentenone predominated. Organic acids were detected by GC-MS in all extracts and correlated positively (R2 = 0.98) with titratable acidity. The GC-MS data showed that phenolic compounds constituted a major portion of Code 10-Poly, and were detected only in trace quantities in 1291. The refined liquid smokes had lighter color, lower acidity, and reduced level of carbonyl-containing compounds and organic acids. Our study revealed major differences in pH, titratable acidity, total phenol content, color and chemical make-up of the full-strength and refined liquid smokes. The three refined liquid smoke products studied have less flavor and color active compounds, when compared with the full-strength product. Furthermore, the three refined products studied have unique chemical characteristics and will impart specific sensorial properties to food systems. Understanding the chemical composition of liquid smokes, be these refined or full-strength products, is an important step to establish their functions and appropriate use in food systems.

Stabilizing Oils from Smoked Pink Salmon (Oncorhynchus gorbuscha)

Smoking of meats and fish is one of the earliest preservation technologies developed by humans. In this study, the smoking process was evaluated as a method for reducing oxidation of pink salmon (Oncorhynchus gorbuscha) oils and also maintaining the quality of oil in aged fish prior to oil extraction. Salmon heads that were subjected to high temperatures (95 degrees C) during smoking unexpectedly produced oils with fewer products of oxidation than their unprocessed counterparts, as measured by peroxide value (PV), thiobarbituric acid reactive substances (TBARS), and fatty acids (FA). Higher temperatures and longer smoking times resulted in correspondingly lower quantities of oxidative products in the oils. Fatty acid methyl ester (FAME) analysis of smoke-processed oils confirmed that polyunsaturated fatty acids (PUFA) were not being destroyed. Smoke-processing also imparted antioxidant potential to the extracted oils. Even when antioxidants, such as ethoxyquin or butylated hydroxytoluene, were added to raw oils, the smoke-processed oils still maintained lower levels of oxidation after 14 d of storage. However, decreased antioxidant capacity of smoke-processed oils was noted when they were heated above 75 degrees C. Vitamin studies supported the antioxidant results, with smoke-processed oils displaying higher levels of alpha-tocopherol than raw oils. Results suggest that smoking salmon prior to oil extraction can protect valuable PUFA-rich oils from oxidation. Improved preservation methods for marine oils may extend their usefulness when added as a supplement to enhance levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in foods.

Prediction of Oyster Volume and Weight Using Machine Vision

ABSTRACT Fifty oysters each from Florida, Texas, and Alaska were used to develop methods that predict overall volume and weight, and meat volume and weight. Volumes (overall, shell, meat) were measured experimentally by the Archimedes principle. Densities were calculated. Using a machine vision system, the top- and side-view areas of whole oysters were determined. Various simple functions were fit to the view area data to predict whole oyster volume and weight, and meat volume and weight. A new cubic spline method was also developed to predict oyster volumes. The r2 values for the predicted oyster volumes were Texas = 0.92, Florida = 0.85, and Alaska = 0.64.

Feeding soy or fish meal to Alaskan reindeer ( Rangifer tarandus tarandus ) – effects on animal performance and meat quality

Fourteen reindeer (8 steers and 6 females) were used to compare the effects of two different reindeer diets (a feed mix based on barley, brome hay and soybean meal (SBM) or fishmeal (WFM) as protein source) on animal growth performance, feed conversion efficiency and ultimate meat quality. Samples from free-ranging reindeer (n=4; 2 steers and 2 females) on the Seward Peninsula were included to provide comparisons with the traditional reindeer meat produced in Alaska. No significant difference was observed in overall weight gain between the WFM and SBM animals or between females and steers; however, the feed conversion efficiency was significantly higher for the reindeer fed the WFM mix. Carcass dressing percentage from the SBM group was higher compared with the WFM animals. No differences were found in live weight, carcass characteristics, meat pH, temperature decline, shear force, meat color or cooking loss when comparing the treatment groups. The meat samples ( M. longissimus ) from the free-range group had the highest amount of omega-3 fatty acids and also the highest amount of polyunsaturated fatty acids (PUFA). Meat from the animals fed SBM was significantly higher in triglyceride content and lower in phospholipid content compared with the two other groups. No significant differences were found when the trained panel compared the sensory attributes of the meat. Off-flavor attributes related to “wild’ or “gamey” flavor was reported by consumers for samples from the WFM and free-range reindeer (15 and 24 per cent of the consumers, respectively). No “fish-related” flavor was reported. In conclusion, no negative effects in either animal performance or meat quality characteristics by using fish meal as opposed to soybean meal as a protein supplement in a milled reindeer diet were found. Abstract in Swedish / Sammandrag: Utfordring av ren med soja- eller fiskmjol – effekter pa tillvaxt, foderutnyttjande och kottkvalitet I var undersokning ingick 14 renar (8 kastrerade sarvar (harkar)och 6 vajor) for att jamfora effekter av tva olika renfoder (baserade pa korn, ho och soja- (SBM) eller fiskmjol (WFM) som proteintillskott) med avseende pa tillvaxt, foderutnyttjande och kottkvalitet. Kottprover fran naturbetande renar (n=4; 2 harkar och 2 vajor) fran Seward Peninsula inkluderades i studien for att representera kvaliteten pa traditionellt producerat renkott fran Alaska. Inga signifikanta skillnader i tillvaxt observerades, varken mellan SBM- och WFM-grupperna eller mellan harkar och vajor. Foderutnyttjandet var dock signifikant battre hos WFM-renarna. Slaktutbytet var hogst for renarna i SBM-gruppen, daremot rapporterades inga skillnader i levandevikt, slaktkroppsegenskaper, pH-varde och temperatur i ytterfilen, skarmotstand, farg eller vattenhallande formaga i kottet nar de tre grupperna av renar jamfordes (SBM, WFM och naturbetande djur). Kottet fran de naturbetande renarna hade det signifikant hogsta innehallet av bade omega-3-fettsyror och av fleromattade fettsyror. Kott fran SBM-renarna hade det hogsta innehallet av triglycerider och det lagsta innehallet av fosfolipider jamfort med de andra tva grupperna. Den tranade smakpanelen kunde inte hitta nagra skillnader i sensoriska egenskaper hos kottet fran renarna i de tre olika grupperna. I en konsumentundersokning rapporterades kommentarer om olika ”vilt-relaterade” bismaker i kott fran naturbetande renar (24% av konsumenterna) och fran WFM-gruppen (15% av konsumenterna), men inga ”fisk-liknande” bismaker i kottet kunde pavisas. Att byta ut sojamjol mot fiskmjol som proteintillskott i renfoder hade inga negativa effekter pa renarnas tillvaxt, foderutnyttjande eller pa renkottets kvalitet.

Development of a Method to Produce Freeze‐Dried Cubes from 3 Pacific Salmon Species

Freeze-dried boneless skinless cubes of pink (Oncorhynchus gorbuscha), sockeye (Oncorhynchus nerka), and chum (Oncorhynchus keta) salmon were prepared and physical properties evaluated. To minimize freeze-drying time, the kinetics of dehydration and processing yields were investigated. The physical characteristics of the final product including bulk density, shrinkage, hardness, color, and rehydration kinetics were determined. Results showed that freeze-dried salmon cubes from each of the 3 Pacific salmon species can be produced with a moisture content of less that 10% and a(w) less 0.4 and freeze-drying time of 9 h. Processing yields ranged from 26% to 28.4%, depending on fish species. Shrinkage was less than 12% and rehydration of freeze-dried cubes was rapid. The value-added products developed have the potential to be utilized as ingredients for ready-to-eat soups, as snack food, salad topping, and baby finger-food.

Refined liquid smoke: a potential antilisterial additive to cold-smoked sockeye salmon (Oncorhynchus nerka).

Cold-smoked salmon (CSS) is a potentially hazardous ready-to-eat food product due to the high risk of contamination with Listeria monocytogenes and lack of a listericidal step. We investigated the antilisterial property of liquid smokes (LS) against Listeria innocua ATCC 33090 (surrogate to L. monocytogenes) as a potential supplement to vacuum-packaged CSS. A full-strength LS (Code 10-Poly), and three commercially refined fractions (AM-3, AM-10, and 1291) having less color and flavor (lower content of phenols and carbonyl-containing compounds) were tested. In vitro assays showed strong inhibition for all LS except for 1291. The CSS strips were surface coated with AM-3 and AM-10 at 1% LS (vol/wt) with an L-shaped glass rod and then inoculated with L. innocua at 3.5 log CFU/g, vacuum packaged, and stored at 4°C. The LS did not completely eliminate L. innocua but provided a 2-log reduction by day 14, with no growth up to 35 days of refrigerated storage. A simple difference sensory test by 180 untrained panelists showed the application of AM-3 did not significantly influence the overall sensorial quality of CSS. In essence, the application of the refined LS as an antilisterial additive to CSS is recommended.

Protein and Lipid Composition of Walleye Pollock (Theragra chalcogramma) Livers

ABSTRACT The objective of this study was to chemically evaluate the lipid and protein from pollock male and female livers. Pollock livers, regardless of gender, were over 50% lipid, with about 98% of the lipid in the form of triacylglycerides. Protein content of male and female livers was similar at approximately 7%. Most of the fatty acids content was not significantly different between males and females. The abundance of saturated, monounsaturated and polyunsaturated fatty acids in all extracted oils averaged about 20%, 55% and 24%, respectively. The omega-3 and omega-6 fatty acid levels of all livers were approximately 22% and 2.0%, respectively. Only small gender differences were detected between pollock liver lipids and protein. Pollock liver protein is of high quality and extracted oil is a valuable source of omega-3 fatty acids. The contents of most amino acids in the samples were similar for both males and females, and samples had high levels of methionine (3.2 and 3.6%), lysine (6.8 and 7.6%) and other essential amino acids.