Effects of initial albumen quality and mineral oil–chitosan emulsion coating on internal quality and shelf‐life of eggs during room temperature storage

Effects of mineral oil (MO) and mineral oil–chitosan emulsion (MO:CH = 25:75) as coatings on internal quality and shelf‐life of eggs were evaluated during 5‐week storage at 25 °C. Eggs with three different initial albumen qualities [Haugh unit (HU): H = 87.8, M = 75.6 and L = 70.9] were evaluated. As storage time increased, HU and yolk index values decreased whereas weight loss increased. Coating with MO and/or 25:75 MO:CH emulsion could preserve the internal quality for at least 4 more weeks for H‐eggs and at least 3 more weeks for M and/or L‐eggs, all with weight losses <0.92%. All coated eggs had >70% positive purchase intent, and their colour differences at week 0 could not be detected by naked human eye (ΔE^* < 3.0, noncoated eggs as reference). Consumers significantly differentiated freshly MO‐coated from noncoated eggs on overall surface appearance. This study demonstrated that MO and 25:75 MO:CH emulsion coatings could preserve internal quality and prolong shelf‐life of eggs.     

Viscosity changes of chitosan solution affect physico-functional properties and consumer perception of coated eggs during storage

Effects of storage of chitosan (CH) solution on physico-functional properties and consumer perception of CH-coated eggs were evaluated during 5- and 15-weeks storage at 25 °C and 4 °C, respectively. Seven treatments [CH0 (freshly-prepared), CH1 (stored for 1-week at 25 °C), CH1R (1-week, 4 °C), CH3 (3-weeks, 25 °C), CH3R (3-weeks, 4 °C), CH5 (5-weeks, 25 °C), CH5R (5-weeks, 4 °C)] were applied on eggshell. After 5-weeks storage, CH-solution viscosity decreased by 2.56 and 4.6 times, respectively, at 4 °C and 25 °C while pH slightly increased. CH0 preserved grade-A quality for 4-weeks vs. 1-week for noncoated eggs at 25 °C. After 5-weeks, weight loss (%) of coated eggs at 25 °C (6.04–5.59) was lower than that of noncoated eggs (7.44) but higher than that of all eggs at 4 °C (2.93–2.46). Albumen pH increased while emulsion capacity decreased with increased storage time; however, both were insignificantly affected by CH viscosity. Consumers perceived CH0- and CH1R-eggshell to be glossier than noncoated eggs after 5-weeks. Purchase intent was higher for CH-coated eggs (72–77.3%) than for noncoated eggs (61.3%). Overall, viscosity changes of CH-coating solution had lesser impact on quality of CH-coated eggs than did storage temperature/time of eggs.     

Comparisons and correlations of phenolic profiles and anti-oxidant activities of seventeen varieties of pineapple

Major phenolic, β-carotene, and ascorbic acid (AA) contents in 17 pineapple varieties were quantified and compared. Anti-oxidant activities were evaluated using 2,2-Diphenyl-l-picrylhydrazyl (DPPH), 2,2’-Azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), ferric reducing anti-oxidant power (FRAP), and metal chelating capacity (MCC) assays. MD-2 exhibited the highest AA and total phenolic (TP) contents and DPPH and ABTS assay results, but was lower in β-carotene contents. Ripley had the highest total flavonoid (TF) content with a low AA content. Comte de Pairs exhibited the highest MCC and the lowest FRAP values. TP contents and both DPPH and ABTS activities, FRAP values and both AA contents and DPPH activities, and TF contents and ABTS activities were positively correlated. MD-2 exhibited the greatest diversity of phenolics and highest anti-oxidant activities in all assays. Information included herein can be useful for development of pineapple-based food products containing high levels of health promoting anti-oxidants.     

Functional, Nutritional, and Rheological Properties of Protein Powders from Arrowtooth Flounder and their Application in Mayonnaise

ABSTRACT: Arrowtooth flounder soluble protein powder (AFSP) and arrowtooth flounder insoluble protein powder (AFISP) were evaluated for their functional, nutritional, and rheological properties. AFSP and AFISP contained 80% and 79% protein and 5.9% and 14.9% fat, respectively. Yield of AFSP (8.6%) was less than AFISP (13.1%). AFSP and AFISP had desirable essential amino acid and mineral contents. Emulsion stability of AFSP was greater than AFISP. Fat and water absorptions (mL/g protein) were 5.2 and 1.8 for AFSP, respectively, and 3.3 and 4.2 for AFISP Mayonnaises made from AFSP had greater emulsion stability than mayonnaise made from AFISP. Mayonnaises from both AFSP and AFISP possessed pseudoplastic and viscoelastic characteristics.     

Preparation and characteristics of squid pen β‐chitin prepared under optimal deproteinisation and demineralisation condition

Squid (Todarodes pacifica) pen was an excellent source of β‐chitin with 25.5% yield. The optimal condition to prepare squid pen β‐chitin was established: deproteinisation with 3% NaOH for 30 min at 15 psi/121 °C and a solid/solvent ratio of 1:10 (w/v) and a subsequent demineralisation with 1 N HCl for 30 min at room temperature and a solid/solvent ratio of 1:10 (w/v). Squid pen β‐chitin contained 6.29% nitrogen, 0.25% ash, and negligible fat with degree of acetylation of 94.02%, residual amino acid of 0.499 g/100 g and bulk density of 0.28 g mL^?1. Depending on its particle size, squid pen β‐chitin visually looked white (L* = 82.82, a* = ?0.67, b* = 6.31; particle size of 0.15–0.18 mm) or light grey (L* = 62.88, a* = 0.33, b* = 10.66; particle size of 0.425–0.841 mm). Water, fat and dye‐binding capacity of squid pen β‐chitin was 694.67%, 194.03% and 79.81%, respectively.     

Germination Conditions Affect Physicochemical Properties of Germinated Brown Rice Flour

ABSTRACT:  Germinated brown rice has been reported to be nutritious due to increased free gamma-aminobutyric acid (GABA). The physicochemical properties of brown rice (BR) and glutinous brown rice (GNBR) after germination as affected by different steeping times (24, 36, 48, and 72 h depending on the rice variety) and pHs of steeping water (3, 5, 7, and as-is) were determined and compared to those of the nongerminated one (control). As the steeping time increased or pH of steeping water decreased, germinated brown rice flours (GBRF) from both BR and GNBR had greater reducing sugar, free GABA and α-amylase activity; while the total starch and viscosity were lower than their respective controls. GBRFs from both BR and GNBR prepared after 24-h steeping time at pH 3 contained a high content of free GABA at 32.70 and 30.69 mg/100 g flour, respectively. The peak viscosity of GBRF obtained from both BR and GNBR (7.42 to 228.22 and 4.42 to 58.67 RVU, respectively) was significantly lower than that of their controls (255.46 and 190.17 RVU, respectively). The principal component analysis indicated that the important variables for discriminating among GBRFs, explained by the first 2 components at 89.82% of total explained variance, were the pasting profiles, α-amylase activity, and free GABA.     

Oil‐in‐Water Emulsion Exhibits Bitterness‐Suppressing Effects in a Sensory Threshold Study

Little is known about how emulsion characteristics affect saltiness/bitterness perception. Sensory detection and recognition thresholds of NaCl, caffeine, and KCl in aqueous solution compared with oil‐in‐water emulsion systems were evaluated. For emulsions, NaCl, KCl, or caffeine were dissolved in water + emulsifier and mixed with canola oil (20% by weight). Two emulsions were prepared: emulsion 1 (viscosity = 257 cP) and emulsion 2 (viscosity = 59 cP). The forced‐choice ascending concentration series method of limits (ASTM E‐679‐04) was used to determine detection and/or recognition thresholds at 25 °C. Group best estimate threshold (GBET) geometric means were expressed as g/100 mL. Comparing NaCl with KCl, there were no significant differences in detection GBET values for all systems (0.0197 ‐ 0.0354). For saltiness recognition thresholds, KCl GBET values were higher compared with NaCl GBET (0.0822 ‐ 0.1070 compared with 0.0471 ‐ 0.0501). For NaCl and KCl, emulsion 1 and/or emulsion 2 did not significantly affect the saltiness recognition threshold compared with that of the aqueous solution. However, the bitterness recognition thresholds of caffeine and KCl in solution were significantly lower than in the emulsions (0.0242 ‐ 0.0586 compared with 0.0754 ‐ 0.1025). Gender generally had a marginal effect on threshold values. This study showed that, compared with the aqueous solutions, emulsions did not significantly affect the saltiness recognition threshold of NaCl and KCl, but exhibited bitterness‐suppressing effects on KCl and/or caffeine.     

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.