Antimicrobia activity of garlic (Allium sativum L.) and holy basil (Ocimum sanctum L.) essential oils applied by liquid vs. vapour phases

Antimicrobial activity of garlic (Allium sativum L.) and holy basil (Ocimum sanctum L.) essential oils (GEO and HBEO, respectively) was evaluated in liquid vs. vapour phases. Diallyl disulphide and diallyl trisulphide in GEO while eugenol, caryophyllene and methyl eugenol in HBEO were predominant active compounds. Individually, GEO was highly effective in the vapour phase, showing the greatest antimicrobial activity (P ≤ 0.05) against Bacillus cereus and Staphylococcus aureus with complete inhibition, followed by Salmonella typhimurium and Pseudomonas fluorescens, but had no effect on Escherichia coli, Lactobacillus plantarum or Listeria monocytogenes. The combined GEO:HBEO (a 1:1 ratio) at 30 μL demonstrated inhibitive activity against all bacteria tested with complete inhibition against B. cereus and S. aureus. Minimum bactericidal concentration (MBC) of the combined oil was <0.4% v/v, except for P. fluorescens requiring a higher MBC (1.5%, v/v). This study demonstrated potential of the combined GEO:HBEO to be used for food preservation applications.     

Analysis of Duplicated Multiple‐Samples Rank Data Using the Mack–Skillings Test

Appropriate analysis for duplicated multiple‐samples rank data is needed. This study compared analysis of duplicated rank preference data using the Friedman versus Mack–Skillings tests. Panelists (n = 125) ranked twice 2 orange juice sets: different‐samples set (100%, 70%, vs. 40% juice) and similar‐samples set (100%, 95%, vs. 90%). These 2 sample sets were designed to get contrasting differences in preference. For each sample set, rank sum data were obtained from (1) averaged rank data of each panelist from the 2 replications (n = 125), (2) rank data of all panelists from each of the 2 separate replications (n = 125 each), (3) jointed rank data of all panelists from the 2 replications (n = 125), and (4) rank data of all panelists pooled from the 2 replications (n = 250); rank data (1), (2), and (4) were separately analyzed by the Friedman test, although those from (3) by the Mack–Skillings test. The effect of sample sizes (n = 10 to 125) was evaluated. For the similar‐samples set, higher variations in rank data from the 2 replications were observed; therefore, results of the main effects were more inconsistent among methods and sample sizes. Regardless of analysis methods, the larger the sample size, the higher the χ² value, the lower the P‐value (testing H₀: all samples are not different). Analyzing rank data (2) separately by replication yielded inconsistent conclusions across sample sizes, hence this method is not recommended. The Mack–Skillings test was more sensitive than the Friedman test. Furthermore, it takes into account within‐panelist variations and is more appropriate for analyzing duplicated rank data.     

Edible chitosan films on ready-to-eat roast beef for the control of Listeria monocytogenes

The use of chitosan as an edible film was evaluated for its antimicrobial activity against Listeria monocytogenes (LM) on the surface of ready-to-eat (RTE) roast beef. L. monocytogenes, decimally diluted to give an initial inoculation of >6.50logCFU/g, was inoculated onto the surface of RTE roast beef cubes, and air-dried. The samples were dipped into chitosan (high or low molecular weights) solutions dissolved with acetic or lactic acid at 0.5% (w/v) or 1% (w/v) then bagged and refrigerated at 4 degrees C. The bacterial counts were determined on days 0, 7, 14, 21, and 28. The samples were spread plated onto modified Oxford agar plates and incubated at 37 degrees C for 48h. An initial 6.50logCFU/g of L. monocytogenes inoculated onto the surface of the non-coated RTE roast beef increased too >10logCFU/g by day 28. On day 14, L. monocytogenes counts were significantly different for all the chitosan-coated samples from the control counts by 2-3logCFU/g and remained significantly different on day 28. Our results have shown that the acetic acid chitosan coating were more effective in reducing L. monocytogenes counts than the lactic acid chitosan coating. Our study indicated that chitosan coatings could be used to control L. monocytogenes on the surface of RTE roast beef.     

Effects of purification process on rheological properties of catfish oil

Effects of oil refining steps (degumming, neutralizing, bleaching, and deodorizing) on rheological properties of catfish oil were investigated. Four rheological models (Newtonian, Bingham, Herschel-Bulkley, and Casson) were used to fit the experimental data. Refined catfish oil behaves like a Newtonian fluid. Based on the Casson model, the yield stress values of oils gradually decreased after each refining step. The highest shear rate index (0.904) was observed in the deodorized oil. The Casson model was used to predict rheological properties because it works well at both lower and higher shear rates.     

Thermal degradation of FA and catfish and menhaden oils at different refining steps

The thermal degradation (weight loss) of individual FA and of catfish and menhaden oils collected from different refining steps was investigated by thermogravimetric analysis. The heat resistance of FA was partially dependent on chain length and degree of unsaturation. The weight loss of catfish and menhaden oils increased with increased heating temperatures, regardless of the oil refining process. All oil samples (except crude catfish oil) were decomposed after the heating temperature reached 550°C. Based on the thermogravimetric curves, the following thermal stability sequence at different refining steps for both catfish and menhaden oils was proposed: crude > degummed > neutralized > bleached > deodorized oils.     

Mango (Mangifera indica L.) leaf extracts as ingredient for the formulation of functional beverages with biological activity

The biological activity of mango leaf extracts from different mango varieties was evaluated in terms of total phenolic content, flavonoids, antioxidant activity and inhibition of α-amylase and α-glucosidase enzymes. Leaf extract-based beverages were formulated and evaluated for some physicochemical, microbiological and sensory properties. Results indicated that the extract from 'Tommy Atkins' mango leaves had the highest total phenols content (137.08 mg of GAE g⁻¹) and antioxidant activity (DDPH = 38.26 mg TEAC 100 g⁻¹; ABTS = 59.13 mg TEAC 100 g⁻¹). The beverage formulated with 20% leaf extract presented the highest percentage of antioxidant activity (38.63%) and inhibition of enzymes α-amylase (41.9%) and α-glucosidase (37.53%). All beverages presented a yellow hue and consumers rated it with a degree of liking between 4.8 and 7.3 according to a hedonic scale. Results showed that the biological properties of beverages could be an alternative for the control of free radicals and glucose levels.     

Phytosterols in banana (Musa spp.) flower inhibit α‐glucosidase and α‐amylase hydrolysations and glycation reaction

Three phytosterols were isolated from Musa spp. flowers for evaluating their capabilities in inhibiting glucosidase and amylase activities and glycation of protein and sugar. The three phytosterols were identified as β‐sitosterol (PS1), 31‐norcyclolaudenone (PS2) and (24R)‐4α, 14α, 4‐trimethyl‐5α‐cholesta‐8, 25(27)‐dien‐3β‐ol (PS3). IC₅₀ values (the concentration of inhibiting 50% of enzyme activity) of PS1, PS2 and PS3 against α‐glucosidase were 283.67, 11.33 and 43.10 μg mL^?1, respectively. For inhibition of α‐amylase, the IC₅₀ values of PS1, PS2 and PS3 were 52.55, 76.25 and 532.02 μg mL^?1, respectively. PS1 was an uncompetitive inhibitor against α‐amylase with K_m at 5.51 μg mL^?1, while PS2 and PS3 exhibited a mixed‐type inhibition with K_m at 52.36 and 2.49 μg mL^?1, respectively. PS1 and PS2 also significantly inhibited the formation of advanced glycation end products (AGEs) in a BSA–fructose model. The results suggest that banana flower could possess the capability in prevention of the diseases associated with abnormal blood sugar and AGEs levels, such as diabetes.     

Asian carp: A threat to American lakes,a feast on Chinese tables

Asian carp, which are widely distributed in Asia and Europe, are nutritious and popular with consumers. In China, Asian carp is a tasty dish and has been consumed for thousands of years. However, they are considered aggressive invasive species that threaten rivers, lakes, and indigenous species in the United States. Asian carp have proliferated greatly in the water basin of the Mississippi River and its tributaries, and they have caused severe ecological problems over the past 20 years. In recent years, several state governments along the Mississippi River have implemented assistance programs to eliminate invasive Asian carp, but these did not alleviate the threat. We conducted a survey to understand consumers' attitudes toward Asian carp in the United States, and related reports were reviewed to explore the possibility of Asian carp as food fish on American tables. Emphasis is placed on the farming history, functional characteristics, consumption preferences, and successful utilization methods for Asian carp in China. In addition, suggestions and possible utilization methods were proposed to improve the negative impression of Asian carp in the United States. Further research is needed to take full advantage of this huge excellent source of food or health supplements. This review provides ideas and directions for the use of Asian carp in the United States. We believe that through effective cooperation between China and the United States, the negative aspects of Asian carp in the United States could be diminished, and a mutually beneficial situation could be achieved.     

Selected Quality and Shelf Life of Eggs Coated with Mineral Oil with Different Viscosities

ABSTRACT:  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 °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.