Effect of preservatives on microbial safety and quality of smoked blue catfish (Ictalurus furcatus) steaks during room-temperature storage.

The microbial safety and quality of smoked blue catfish (Ictalurus furcatus) steaks treated with antimicrobials and antioxidants were examined during 6-week ambient storage. Five pre-smoking soaking treatments were applied: 25% NaCl and 1% ascorbic acid for 30 min or 1h, 3% sodium lactate with or without 5% rosemary extract for 30 min, and 5% sorbic acid alone for 30 min. After smoking, cooled catfish steaks were packed and analyzed at 0, 2, 4, and 6 weeks of ambient storage. Neither Listeria nor Salmonella was recovered from the smoked catfish steaks. Significant reductions (P<0.05) in total plate counts were observed in all treated samples, with those treated with 3% sodium lactate carrying the lowest microbial load. The rosemary extract-treated samples were the most stable against oxidation. All treated smoked catfish steaks had water activities less than 0.85; however, neither pH nor water activity changed significantly within each treatment group during storage (P> or 0.05). In conclusion, smoking/cooking effectively reduced microbial populations, and the use of antimicrobial agents and antioxidants, particularly 3% sodium lactate, could aid the control of microbial safety during storage, resulting in safe products for up to 6 weeks without refrigeration.

Evaluation of biomolecular interactions of sulfated polysaccharide isolated from Grateloupia filicina on blood coagulation factors.

An edible marine red alga, Grateloupia filicina, collected from Jeju Island of Korea was hydrolyzed by cheap food-grade carbohydrases (Viscozyme, Celluclast, AMG, Termamyl, and Ultraflo) to investigate its anticoagulant activity. Among the tested enzymatic extracts of G. filicina, a Termamyl extract showed the highest anticoagulant activity. Anion-exchange chromatography on DEAE-cellulose and gelpermeation chromatography on Sepharose-4B were used to purify the active polysaccharide from the crude polysaccharide fraction of G. filicina. The purified sulfated polysaccharide (0.42 sulfate/total sugar) showed approximately 1,357 kDa molecular mass and was comprised mainly of galactose (98%) and 1-2% of glucose. The sample showed potential anticoagulant activity on activated partial thromboplastin time (APTT) and thrombin time (TT) assays. The purified G. filicina anticoagulant (GFA) inhibited the coagulation factor X (92%), factor II (82%), and factor VII (68%) of the coagulation cascade, and the molecular interaction (protein-polysaccharide) was highly enhanced in the presence of ATIII (antithrombin III). The dissociation constant of polysaccharide towards serine proteins decreased in the order of FXa (58.9 nM) >FIIa (74.6 nM) >FVII (109.3 nM). The low/less cytotoxicity of the polysaccharide benefits its use in the pharmaceutical industry; however, further studies that would help us to elucidate the mechanism of its activity are needed.

Assessing Consumer Emotional Responses in the Presence and Absence of Critical Quality Attributes: A Case Study with Chicken Eggs.

UNLABELLED: Effects of attribute presence and absence on the emotional profile and consumer acceptability of products with varying qualities were assessed using eggs as an example. An online survey (n = 320) was used to evaluate emotional responses and acceptability to 5 types of egg quality attributes: intrinsic, aesthetic, extrinsic, expediency, and wholesome/safety, for both present and absent conditions. Attribute absence rather than presence evoked greater consumer discriminating emotions associated with eggs. Mean emotion intensity elicited by the presence of all quality attributes ranged from 1.67 (intrinsic; guilty) to 4.05 (wholesome; good) versus 2.01 (wholesome; satisfied) to 3.29 (wholesome; disgusted) when absent. Key positive emotions elicited by presence of attributes were active, calm, good, interested, happy, safe, and satisfied; while dominant negative emotions elicited by absence of attributes included disgusted and worried. Wholesome quality (constituted by egg freshness, "packing/best-before-date" and absence of visible cracks) exhibited the highest liking (7.65) and emotion intensities, while the emotional responses to both the presence and absence of intrinsic quality (constituted by nutrient-fortified egg, organic egg, and USDA-certified farm egg) were similar, reflecting their dynamic effects on emotions. Emotions and acceptability were more correlated for attribute absence than presence; and good, happy, and satisfied emotions were strongly related to egg acceptability (r ≥ 0.6). Egg product/packaging design can be oriented toward emphasizing wholesome and expedient attributes, since they enhance good, safe, and satisfied emotions, while minimizing disgust, worry, and boredom. The use of emotional responses and hedonic testing regarding attribute presence and absence would allow for improved selection of attributes critical to consumer acceptance of products. PRACTICAL APPLICATION: Assessing effects of attribute presence compared with absence on food-evoked emotions may offer valuable insights for differentiation of competing or otherwise similar products. Affective consumer responses to food products with varying sensory and quality attributes are influenced by several factors including psychographics, demographics, product category, and test design. In this study, a scenario is depicted where product developers can identify critical product features based on emotional assessment of products with and without quality attributes. This study is beneficial to product developers and the egg industry, as it identifies opportunities to better understand consumer needs, thereby, designing products destined for success in the marketplace.

Antibacterial activity of chitosans and chitosan oligomers with different molecular weights.

Antibacterial activities of six chitosans and six chitosan oligomers with different molecular weights (Mws) were examined against four gram-negative (Escherichia coli, Pseudomonas fluorescens, Salmonella typhimurium, and Vibrio parahaemolyticus) and seven gram-positive bacteria (Listeria monocytogenes, Bacillus megaterium, B. cereus, Staphylococcus aureus, Lactobacillus plantarum, L. brevis, and L. bulgaricus). Chitosans showed higher antibacterial activities than chitosan oligomers and markedly inhibited growth of most bacteria tested although inhibitory effects differed with Mws of chitosan and the particular bacterium. Chitosan generally showed stronger bactericidal effects with gram-positive bacteria than gram-negative bacteria in the presence of 0.1% chitosan. The minimum inhibitory concentration (MIC) of chitosans ranged from 0.05% to >0.1% depending on the bacteria and Mws of chitosan. As a chitosan solvent, 1% acetic acid was effective in inhibiting the growth of most of the bacteria tested except for lactic acid bacteria that were more effectively suppressed with 1% lactic or formic acids. Antibacterial activity of chitosan was inversely affected by pH (pH 4.5-5.9 range tested), with higher activity at lower pH value.

Comparison of physicochemical, binding, and antibacterial properties of chitosans prepared without and with deproteinization process.

Physicochemical, binding, and antibacterial properties of chitosans prepared without and with deproteinization (DP) process (5, 10, 15, and 30 min at 15 psi/121 degrees C) were compared. Chitosan from DP 0 min had comparable nitrogen content, lower degree of deacetylation and solubility, but higher molecular weight and viscosity than chitosans from DP 5-30 min. The latter four chitosans showed differences only in molecular weight. Deproteinization treatment resulted in slightly decreased L values and increased a and b values compared with those of DP 0 min. Chitosan from DP 0 min had comparable water and fat-binding capacity (FBC) except for chitosan from DP 15 min, which had a higher FBC but lower dye-binding capacity than those of the four chitosans from DP 5-30 min. The antibacterial activities of chitosans against seven different bacteria showed that the inhibitory effects varied with the deproteinization time and the particular bacterium.

Oil coating affects internal quality and sensory acceptance of selected attributes of raw eggs during storage.

UNLABELLED: Four (coconut, palm, rice bran, and soybean) edible oils and glycerol were applied on eggshell. All noncoated and coated eggs were stored for 5 wk at 25 ± 2 °C and drawn weekly for quality evaluation. All oil coatings were more effective in preserving internal quality of eggs than was glycerol coating. As storage time increased, the preservative effects of edible oil coating on weight loss, and albumen and yolk quality were significantly noticed. Oil-coated eggs had significantly lower weight loss (<0.43%) than did noncoated (3.87%) and glycerol-coated (3.73%) eggs after 5 wk of storage. Based on the Haugh unit, oil-coated eggs maintained AA grade up to 3 wk. After 5 wk of storage, noncoated, glycerol-coated, and oil-coated eggs changed from AA grade to below B, below B and A grade, respectively. The albumen pH of noncoated and glycerol-coated eggs considerably increased from 8.23 to 9.51 and 9.42, respectively, while those of oil-coated eggs either maintained or slightly increased to 8.32. The albumen viscosity of all eggs decreased with increased storage time. Consumers (N = 120) could differentiate surface glossiness of oil-coated eggs from uncoated eggs (R-index of 81.42% to 86.99%). All oil-coated eggs were acceptable for surface glossiness (liking scores of 6.22 to 6.77) and surface odor (liking scores of 6.20 to 6.55) with overall liking scores of 6.34 to 7.03. Overall, this study demonstrated that edible oil (coconut, palm, rice bran, and soybean) coating could preserve internal quality of eggs (maintaining grade A) at least 4 wk longer than noncoated eggs. PRACTICAL APPLICATION: Freshness is a major contribution to the egg quality. The internal quality of eggs begins to deteriorate after they have been laid due to loss of moisture and carbon dioxide via the eggshell pores. Refrigeration is very effective in preserving egg quality. Surface coating is an alternative method to preserve egg quality, although it is much less effective than refrigeration. This study demonstrated that coconut, rice bran, soybean, and palm oils, which are abundant and commonly consumed in many parts of the world, could preserve the internal quality and reduce weight loss of oil-coated eggs during room temperature storage.

Anti-inflammatory activities of an ethanol extract of Ecklonia stolonifera in lipopolysaccharide-stimulated RAW 264.7 murine macrophage cells.

Ecklonia stolonifera is a brown alga that was shown to have antioxidant, anti-inflammatory, tyrosinase inhibitory, and chemopreventive activities. However, the molecular mechanisms underlying its anti-inflammatory activity remain unclear. In this study, we investigated the molecular mechanism of the anti-inflammatory action of E. stolonifera ethanolic extracts (ESE) using lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. ESE inhibited LPS-induced nitric oxide (IC(50) = 72 ± 1.9 µg/mL) and prostaglandin E(2) (IC(50) = 98 ± 5.3 µg/mL) production in a dose-dependent manner and suppressed the expression of inducible nitric oxide synthase and cyclooxygenase-2 in RAW 264.7 cells. ESE also reduced the production of pro-inflammatory cytokines in LPS-stimulated RAW 264.7 cells. LPS-induced nuclear factor-κB (NF-κB) transcriptional activity and NF-κB translocation into the nucleus were significantly inhibited by ESE treatment through the prevention of the degradation of inhibitor κB-α. Moreover, ESE inhibited the activation of Akt, ERK, JNK1/2, and p38 MAPK in LPS-stimulated RAW 264.7 cells. The main components with anti-inflammatory activity in ESE were identified as phlorofucofuroeckol A and B based on the inhibition of NO production. Our results indicate that ESE can be considered as a potential source of therapeutic agents for inflammatory diseases.

Internal quality and shelf life of eggs coated with oils from different sources.

UNLABELLED: Selected internal quality and shelf life of eggs coated with oils from differences sources (mineral oil, canola oil, corn oil, grape seed oil, olive oil, soybean oil, and sunflower oil) were evaluated during 5 wk of storage at 25 °C. As the storage time increased, weight loss increased whereas Haugh unit and yolk index values decreased. Throughout the 5 wk of storage, eggs coated with oils, regardless of oil sources, possessed better albumen and yolk quality than the control noncoated eggs. Oil coating minimized weight loss of eggs (<0.8%) compared with that (7.26%) of the noncoated eggs after 5 wk of storage at 25 °C. No significant differences in internal quality (weight loss, Haugh unit, yolk index, and albumen pH) were generally observed among oil-coated eggs during 5 wk of storage. Based on the Haugh unit, the grade of noncoated eggs changed from AA at 0 wk to A at 1 wk and to B after 3 wk whereas that of oil-coated eggs from AA at 0 wk to A at 4 wk and maintained A grade until 5 wk. This study demonstrated that oil coating, irrespective of oil sources, preserved the internal quality, minimized weight loss (<0.8%), and extended the shelf life of eggs by at least 3 wk longer than observed for the noncoated eggs at 25 °C storage. Soybean oil was a more practical option as a coating material for eggs due to its low cost. PRACTICAL APPLICATION: Eggs are highly perishable and susceptible to internal quality deterioration when stored above 7 °C. Refrigeration of eggs may be seldom practiced in some developing regions of the world. Therefore, an alternative method, that is inexpensive yet effective, to preserve the internal quality of eggs and to prevent microbial contamination is needed. Oil coating has been proven to preserve the internal quality, prolong shelf life, and minimize weight loss of eggs. This study demonstrated that, compared with other vegetable oils, soybean oil was a more practical option as a coating material for eggs during 5 wk of storage at 25 °C due to its low cost.

Mineral oil-chitosan emulsion coatings affect quality and shelf-life of coated eggs during refrigerated and room temperature storage.

Effects of mineral oil (MO) and 4 emulsions (prepared with different emulsifier types) of MO and chitosan solution (CH) at a fixed ratio of MO:CH = 25:75 as coating materials in preserving the internal quality of eggs were evaluated during 5 wk at 25 °C and 20 wk at 4 °C. Generally, as storage time increased, Haugh unit and yolk index values decreased whereas weight loss increased. However, MO and/or 4 emulsion coatings minimized the weight loss (<1.5%) and preserved the albumen and yolk quality of eggs (with the final B grade) for at least 3 wk longer than those observed for noncoated eggs at 25 °C. At 4 °C, all coated eggs changed from AA to A grade after 5 wk and they maintained this grade for 10 wk (5 wk longer than that of noncoated eggs). Although refrigeration (4 °C) alone could maintain the B grade of noncoated eggs for up to 20 wk, coating treatments were necessary to keep the weight loss below 2%. Compared with 4 °C, the increasing weight loss showed stronger negative correlation (P < 0.01) with the decreasing Haugh unit (-0.46 to -0.89) and yolk index (-0.36 to -0.89) at 25 °C. The emulsifier type used in this study generally did not affect the internal quality of eggs. Salmonella spp. detection was negative for all coated and noncoated eggs. This study demonstrated that MO and MO:CH emulsion coatings preserved the internal quality, prolonged the shelf-life, and minimized weight loss (<2%) of eggs.

Physicochemical properties and consumer acceptance of wheat-germinated brown rice bread during storage time.

Selected physicochemical properties and consumer acceptance of bread prepared from composite flour (wheat:germinated brown rice:germinated glutinous brown rice flours at 60:30:10 ratio) were evaluated during storage for 0, 3, and 5 d, and compared with wheat bread (0 d, control). During storage, color profiles and water activity (from 0.947 to 0.932) of crumbs of composite flour breads slightly changed, but moisture content drastically decreased along with increasing crumb hardness (from 4.16 N to 10.37 N). Higher retrogradation in bread crumb was observed particularly for 5-d stored bread (DeltaH = 2.24 J/g) compared to that of the fresh composite bread and the control (DeltaH = 0.70 and 0.51 J/g, respectively). Mean (n = 116) overall liking score of the fresh composite flour bread (0 d) was slightly lower than that of the control (7.1 compared with 7.6 based on a 9-point hedonic scale). At least 76% of consumers would purchase the fresh composite flour bread if commercially available. Breads were differentiated by textural (moistness, smoothness, and softness) acceptability with canonical correlation of 0.84 to 0.87. The signal-to-noise ratio values of the 5-d stored breads were lower than the control, due mainly to the non-JAR (not-enough) intensity responses for moistness, smoothness, and softness; the mean drop of liking scores for these attributes ranged from 2.42 to 2.98. Flavor acceptability and overall liking were factors influencing consumers' purchase intent of composite flour breads based on logistic regression analysis. This study demonstrated feasibility of incorporating up to 40% germinated brown rice flour in a wheat bread formulation. Practical Application: Our previous study revealed that flours from germinated brown rice have better nutritional properties, particularly gamma-aminobutyric acid (GABA), than the nongerminated one. This study demonstrated feasibility of incorporating up to 40% germinated brown rice flour in a wheat bread formulation. In the current U.S. market, this type of bread may be sold as frozen bread that would have a longer shelf life, or may be supplied as a food-service product that would be made-to-order or made fresh daily as currently practiced in some major grocery stores.

Stability of chitosan powder during long-term storage at room temperature.

Physicochemical and functional properties of two chitosan products [low viscosity (LV) with 16.8 mPa s; high viscosity (HV) with 369.4 mPa s] were evaluated during 9-month storage at room temperature. As storage time increased, increased moisture content and DPPH radical scavenging activity and decreased viscosity and water binding capacity (WBC) were observed. The extent (%) of decreased viscosity and WBC and of increased DPPH radical scavenging activity during storage were more pronounced with the HV chitosan. Significant correlations were observed between WBC and viscosity (r = 0.88 for LV; r = 0.96 for HV) and between DPPH radical scavenging activity and viscosity (r = -0.79 for LV; r = -0.87 for HV). Although significant differences in L*a*b* values were observed during storage, color differences were not easily discerned visually. Antibacterial activity of the HV chitosan against two Gram-negative and two Gram-positive bacteria significantly increased with increasing storage time.

Selected quality and shelf life of eggs coated with mineral oil with different viscosities.

Selected quality and shelf life of eggs coated with mineral oil having 6 different viscosities (7, 11, 14, 18, 22, and 26 cP) were evaluated during 5 wk of storage at 25 degrees C. As the storage time increased, weight loss and albumen pH increased whereas Haugh unit and yolk index values decreased. After 5 wk of storage, eggs coated with 11, 14, 18, 22, or 26 cP oil possessed better quality than the control noncoated eggs and eggs coated with 7 cP oil. Oil coating, irrespective of viscosities, did not improve the emulsion capacity. There was an observable trend that coating with 26 cP oil was more effective in preventing weight loss and in maintaining the Haugh unit of eggs compared with coating with other viscosities of mineral oil. Based on the Haugh unit, the grade of noncoated eggs changed from "AA" at 0 wk to "C" after 3 wk whereas that of 26 cP oil-coated eggs from "AA" at 0 wk to "A" at 3 wk and "B" at 5 wk of storage. Coating with 26 cP oil reduced the weight loss of eggs by more than 10 times (0.85% compared with 8.78%) and extended the shelf life of eggs by at least 3 more weeks compared with the noncoated eggs.

Sensory optimization of a mayonnaise-type spread made with rice bran oil and soy protein.

The optimum formulation for mayonnaise-type spreads containing rice bran oil (RBO) and soy protein concentrate (SPC) was determined based on sensory acceptability. RBO and SPC were used due to their health benefit claims such as lowering risk of heart disease. The effects of the proportions of high-impact ingredients (RBO, SPC, and water) on sensory acceptability of the spreads were determined. The 10 spread formulations, prepared following a 3-component constrained simplex lattice mixture design, were subjected to a consumer acceptance test to identify sensory attributes driving consumer acceptance and purchase intent. Predictive regression models were used to plot mixture response surfaces of the critical sensory attributes (taste, mouthfeel, and overall liking) that influenced purchase intent. Areas within the contour plots of these critical sensory attributes, having acceptability scores > or = 68 ("moderately like" on the 100-mm bidirectional labeled affective magnitude scale) were chosen and superimposed to obtain a predicted optimum formulation range (37% to 43% RBO, 4% to 7% SPC, and 52% to 57% water). The formulation containing 37% RBO, 6% SPC, and 57% water, which was located within the optimum region, was selected as a base for further developing flavored (sour cream & onion, cheddar & sour cream, or Monterrey Jack dried cheese) products. All flavored spreads were significantly more acceptable than the plain formulation. Purchase intent of all flavored products also significantly increased once consumers had been given the information about potential health benefits associated with RBO and SPC in the spreads.

Effect of molecular weight, type of chitosan, and chitosan solution pH on the shelf-life and quality of coated eggs.

Effects of the molecular weight and type of chitosans and pH of chitosan solution on antibacterial activity against Salmonella enterica Enteritidis and on internal quality of chitosan-coated eggs were evaluated during 4 wk of storage at 25 degrees C. Two types of chitosans were studied: alpha-chitosans with 4 different molecular weights (Mw = 282, 440, 746, and 1110 kDa) and beta-chitosan (Mw = 577 kDa). The alpha-chitosan with 282 kDa exhibited stronger bactericidal effects than did other alpha- and beta-chitosans. The weight loss, Haugh unit, and yolk index values suggested that coating of eggs with alpha-chitosan with 282 kDa increased the shelf-life of eggs by almost 3 wk at 25 degrees C compared with noncoated eggs. The pH (4.5, 5.0, and 5.5) of the alpha-chitosan (282 kDa) solution did not affect the internal quality of chitosan-coated eggs. Therefore, coating of eggs with 282 kDa alpha-chitosan without pH adjustment (initial pH of 4.5) may offer a protective barrier against contamination of S. Enteritidis while simultaneously preserving the internal quality of eggs.