Functionalities of Gelatin Modified with 2-Octenyl Succinic Anhydride and Gallic Acid.

The aim of this research was to modify gelatin (GT) with 2-octenyl succinic anhydride (OA) and gallic acid (GA) and investigate its functionalities. GT modified with OA (GT-OA) has an improved water solubility at room temperature and an enhanced surface activity, foaming capacity, and pH buffering ability. Regarding antioxidant activity, GT-OA grafted with GA to generate the compound GT-OA-GA has shown good antioxidant activity. Particularly, GT-OA-GA surpassed GA in ferrous ion (Fe2+)-chelating activity. With respect to antimicrobial activity, GT-OA-GA could be complexed with zinc ions (Zn2+), and this complex exhibited good antimicrobial activity against Staphylococcus aureus and Escherichia coli (O157:H7). Chemically modified GT has better water solubility at room temperature and more functionalities than unmodified GT. Thus, it can be used as an emulsifier or coating material in food, cosmetic, and pharmaceutical industries pertaining to GT applications.

Functionalities of chitosan conjugated with lauric acid and l-carnitine and application of the modified chitosan in an oil-in-water emulsion.

The aim of this research was to conjugate chitosan (CT) with lauric acid (LA) and l-carnitine (CNT) to yield a product that is water-soluble at neutral pH and has surface, antimicrobial, and antioxidant activities. The resulting CT-LA-CNT is water-soluble at neutral pH, in contrast with CT and CT-LA, which require the aid of acid to become soluble. Concerning antimicrobial activity, for S. aureus, the minimum bactericidal concentration of CT was lower than those of CT-LA or CT-LA-CNT, while the three compounds exhibited similar bactericidal activity against E. coli. CT-LA-CNT was also used to study the oxidative stability of soybean oil in an oil-in-water (O/W) emulsion; sodium dodecyl sulfate (SDS) and Tween 80 and Span 80 (TS), an emulsifier mixture, were used as controls for comparison. The results showed that CT-LA-CNT was better than SDS and TS at protecting the lipid from oxidation.

Composition and Insecticidal Activity of Essential Oil of Bacopa caroliniana and Interactive Effects of Individual Compounds on the Activity.

Bacopa caroliniana (BC) is a perennial creeping herb and popular aquarium plant. This plant is easily cultivated; consequently, it has the potential to be a raw material which is readily available for mass production if it contains useful bioactive substances. The information about the functionality of this plant has been very limited. Therefore, the aims of this research were to analyze the composition of the essential oil (EO) of BC and to study its insecticidal effect on rice weevils. Moreover, the interactive effects of active compounds of the EO on this activity were also investigated. A total of 18 volatile compounds was identified, accounting for ca. 94% of the BC-EO in terms of quantity. Of them, α-terpinolene was the largest compound. The impact of individual volatile compounds on the inhibition of acetylcholine esterase and insecticidal activity were determined. α-Terpinolene exhibited the highest activity on these assays. Both additive and synergistic effects existed in terms of the insecticidal activity. Many compounds found in the BC-EO are widely present in other EOs. Thus, the information obtained from this study is useful for EO-related research, applications in selecting EOs or in seeking the best combination of EOs or individual compounds to achieve efficient insecticidal effects.

Functionalities of chitosan conjugated with stearic acid and gallic acid and application of the modified chitosan in stabilizing labile aroma compounds in an oil-in-water emulsion.

The aims of this research were to conjugate chitosan (CT) with stearic acid (SA) and gallic acid (GA), and apply the modified chitosan to stabilize labile aroma compounds such as allyl isothiocyanate (AITC) and limonene in oil-in-water emulsions. Generally, the antioxidant activity of CT-SA-GA increased as the GA content in the conjugate increased. In most assays, GA had a lower IC50 value than that of CT-SA-GA; however, CT-SA-GA exhibited better performance than GA in the Fe2+-chelating activity. In accelerated tests (heating or illumination) for evaluating the chemical stability of AITC and limonene during storage, CT-SA and CT-SA-GA were used to prepare AITC and limonene O/W emulsions, respectively. Tween 80 and Span 80 (T-S-80), an emulsifier mixture, were used as a control in both emulsions for comparison. The results show that CT-SA or CT-SA-GA could protect AITC or limonene from degradation or oxidation more effectively than T-S-80.

Effects of processing methods on composition and functionality of volatile components isolated from immature fruits of atemoya.

Atemoya is one of the most important commercial fruits of the family Annonaceae. The immature fruits of atemoya amply produced from a fruit-thinning process is normally regarded as waste and discarded. This research aimed at studying antimicrobial, antioxidant, and anti-inflammatory activities of the essential oil (EO) isolated from the immature fruits to explore its potential application. The fruits were subjected to different drying methods: solar drying (SD), oven drying at 30°C (OD-30), and at 50°C (OD-50). The oven drying method gave a higher EO yield than the solar drying method. Spathulenol was the largest compound in the EO after the drying process. Antimicrobial effect was not affected by the different drying methods. Antioxidant activity of the EO was measured by DPPH, nitric oxide, and reducing power methods. The EOOD-50 exhibited a stronger antioxidant activity than EOSD and EOOD-30. The EO also showed an anti-inflammatory activity in a cell model.

Functionalities of conjugated compounds of γ-aminobutyric acid with salicylaldehyde or cinnamaldehyde.

Aldehydes or ketones can react with amino compounds to form Schiff base adducts, which have been widely studied and shown to exhibit antimicrobial, antioxidant or antiviral activity. Salicylaldehyde (SA) and cinnamaldehyde (CA) are components of plant essential oils. γ-Aminobutyric acid (GA) is an important substance in the mammalian central nervous system and responsible for many bioactivities. This study aimed to synthesize functional Schiff base adducts using GA and SA or CA; to study the antimicrobial activity, antioxidant activity and tyrosinase-inhibition activity of these adducts (SA-GA and CA-GA) and their metal complexes--SA-GA-Cu (or Zn) and CA-GA-Cu (or Zn); and to find their applications in food systems. SA-GA and CA-GA both exhibited good antibacterial effects, and so did their Cu complexes. As for antioxidant activity, SA-GA and CA-GA were superior to their metal complexes in most tests. Regarding inhibition of enzymatic browning of mushrooms, both SA-GA-Cu and CA-GA-Cu could inhibit tyrosinase activity effectively.

Antimicrobial activity of the essential oil of Glossogyne tenuifolia against selected pathogens.

BACKGROUND: Glossogyne tenuifolia (GT) is a perennial herb widely distributed in the areas from south Asia to Australia. Many biological effects of G. tenuifolia have been reported; however, the information about antimicrobial activity of the essential oil (EO) of the herb remains unavailable. Therefore, the aims of this study were to investigate the antimicrobial activity of the GT-EO in vitro and food systems, the antimicrobial impact (AI) of its individual compounds, and interactive effects of major active compounds (linalool, 4-terpineol, α-terpineol, ρ-cymene) on selected Gram-positive (S. aureus, L. monocytogenes, S. mutans and S. sanguinis) and Gram-negative (E. coli O157:H7, V. parahaemolyticus and S. enterica) pathogens. RESULTS: The minimal microbicidal concentration (MMC) of the GT-EO ranged from 0.75 to 12 mg mL(-1) against the test bacteria in vitro. Except for L. monocytogenes, the GT-EO exhibited more inhibitory effect on the selected Gram positive than against the Gram negative bacteria at the GT-EO concentrations ≤ 12 mg mL(-1) . The interactive effects of major active compounds (linalool, 4-terpineol, α-terpineol, ρ-cymene) are additive instead of synergistic via the checkerboard analysis. The bacteria with a microbial load of ca. 10(2) CFU mL(-1) in the milk tea could be completely inactivated by the GT-EO with the MMC of 1.5 mg mL(-1) . CONCLUSION: ρ-Cymene is the largest component in the GT-EO; however, it is not the compound predominantly affecting the entire antimicrobial activity of the EO. Instead, 4-terpineol is the most influential among the test compounds that contribute to the antimicrobial activity of the GT-EO.

Application of power plant flue gas in a photobioreactor to grow Spirulina algae, and a bioactivity analysis of the algal water-soluble polysaccharides.

A novel photobioreactor was developed with a total volume of 30 m(3) which required merely 100 m(3) of land footprint. The bioreactor was capable of utilizing CO(2) in the flue gas of a power plant as the carbon source for the growth of a freshwater alga, Spirulina platensis, mitigating the greenhouse effect caused by the same amount of CO(2) discharge. Results of the study indicated that the photobioreactor was capable of fixing 2,234 kg of CO(2) per annum. Upon deducting the energy consumption of operating the bioreactor unit, the estimated amount of CO(2) to be fixed by a scaled-up reactor would be 74 tons ha(-1)year(-1). In addition, the study prove that protein-free polysaccharides of S. platensis could induce the production of pro-IL-1 and IL-1 proteins through the mediation of ERK, JNK, and p38 MAPKs pathways. As a consequence, immunogenic activities of the macrophage cells were enhanced.

Antimicrobial impact of the components of essential oil of Litsea cubeba from Taiwan and antimicrobial activity of the oil in food systems.

Using natural additives to preserve foods has become popular due to consumer demands for nature and safety. Antimicrobial activity is one of the most important properties in many plant essential oils (EOs). The antimicrobial activity of the essential oil of Litsea cubeba (LC-EO) from Taiwan and the antimicrobial impact of individual volatile components in the oil on pathogens or spoilage microorganisms: Vibrio parahaemolyticus, Listeria monocytogenes, Lactobacillus plantarum, and Hansenula anomala in vitro, and the antimicrobial activity of the LC-EO against these organisms in food systems were studied. The "antimicrobial impact" (AI) is a new term that combines the effects of minimal microbicidal concentration (MMC) and quantity of an antimicrobial substance. The AI can quantitatively reflect the relative importance of individual components of the EO on the entire antimicrobial activity of the EO. The MMCs of the LC-EO against V. parahaemolyticus, L. monocytogenes, L. plantarum, and H. anomala were determined as 750, 750, 1500, and 375 µg/g, respectively in vitro. The MMCs of the LC-EO were 3000, 6000, and 12,000 µg/g for L. monocytogenes in tofu stored at 4 °C, 25 °C, and 37 °C, respectively. The temperature affected the bacterial growth which consequently influenced the MMCs of the LC-EO. The MMCs of the LC-EO were 3000, 6000, and 375 µg/g for Vibrio spp. in oysters, L. plantarum in orange-milk beverage, and H. anomala in soy sauce, respectively. Except for soy sauce, the food systems exhibited marked matrix effects on diminishing the antimicrobial activity of the LC-EO. Averagely, citral accounted for ca 70% of the total AI value for all the tested organisms, and the rest of the AI value of the LC-EO was determined by all the tested compounds (ca 4%) and the unidentified compounds (ca 26%).

Effects of lecithin and pectin on riboflavin-photosensitized oxidation of orange oil in a multilayered oil-in-water emulsion.

The effects of lecithin and pectin on riboflavin-photosensitized oxidation of orange oil in a multilayered oil-in-water emulsion are studied by response surface methodology. Lecithin and pectin contents are two variables studied. Mean oil droplet size, viscosity, and ζ-potential are investigated for evaluation of emulsion stability. Headspace oxygen depletion, increase of conjugated diene value, and released amounts of limonene and carvone are used as responses to evaluate the oxidative stability of orange oil in this emulsion. The results show that both lecithin and pectin contents have significant effects (p < 0.05) on the oxidative stability of orange oil in the multilayered emulsion during photosensitized oxidation. No interactive effect (p < 0.05) is found between the lecithin and pectin contents. To achieve optimal oxidative stability, the suggested values in ratio for lecithin and pectin contents are 14.1 ± 0.5 and 19 ± 0.7, respectively.

Stability and antimicrobial activity of allyl isothiocyanate during long-term storage in an oil-in-water emulsion.

This study investigated the stability and antimicrobial activity of allyl isothiocyanate (AITC) in medium chain triglyceride (MCT) or soybean oil (SBO) dispersed in an oil-in-water (o/w) system during long-term storage. Oil type, content, and oxidative stability affect the stability and antimicrobial activity of AITC during storage. High oil content is favorable for AITC stability in the emulsion. Notably, AITC with MCT is more stable than AITC with SBO with the same oil content. Consequently, AITC with MCT is more effective than AITC with SBO in inhibiting G(-) bacteria (E. coli O157:H7, Salmonella enterica, and Vibrio parahaemolyticus) and G(+) bacteria (Staphylococcus aureus and Listeria monocytogenes).

Quenching mechanism and kinetics of ascorbic acid on the photosensitizing effects of synthetic food colorant FD&C Red Nr 3.

The pH effect on the oxidative stability of ascorbic acid in the presence of food colorant FD&C Red Nr 3 during storage with or without light was investigated. The quenching mechanism and kinetics of ascorbic acid on the FD&C Red Nr 3 photosensitized oxidation in an aqueous system at 25 degrees C were also studied by measuring the degradation of ascorbic acid or depletion of headspace oxygen. Red Nr 3 had no influence on the oxidation of ascorbic acid under dark storage, but accelerated its oxidation rate under light storage. The oxidative stability of ascorbic acid decreased as the pH increased from 4 to 7 under light without FD&C Red Nr 3. The quenching rates of ascorbic acid on the singlet oxygen by measuring the degradation of ascorbic acid in the presence of Red Nr 3 under light storage were 1.53 +/- 0.15 x 10(8), 1.86 +/- 0.25 x 10(8), and 1.19 +/- 0.12 x 10(8) M(-1)S(-1) at pH 4, 5.6, and 7, respectively.

Optimization of production of conjugated linoleic acid from soybean oil.

Linoleic acid from soybean oil was used to synthesize conjugated linoleic acid (CLA), and the response surface methodology (RSM) was applied to optimize the process. A temperature of -35 degrees C and a solvent to oil sample ratio of 8 were suggested for removal of saturated fatty acids by low-temperature crystallization. The ratio of oil sample/urea/methanol suggested was 1:2:5.5 (w/w/v) for removal of oleic acid by urea crystallization. A temperature of 150 degrees C and a time of 140 min were found to be the optimal conditions in the isomerization for the production of c-9,t-11 and t-10,c-12 CLA isomers.

Optimization of solid-phase microextraction analysis for studying change of headspace flavor compounds of banana during ripening.

The changes of headspace flavor compounds of banana during ripening were studied by a solid-phase microextraction (SPME) method. Three temperatures, 20, 25, and 30 degrees C, were used to investigate the temperature effect on the changes of headspace flavor compounds of banana during ripening over a period of 8 days. Banana juice concentration, salt concentration, time, and temperature were investigated for optimizing the SPME method. The most suitable concentrations of banana juice and salt were 33.3 and 20%, respectively. The optimal temperature and time are about 50 degrees C and 48 min, respectively. Increasing ripening temperature could accelerate ripening rate. Ethanol developed most rapidly at 30 degrees C, whereas amounts of the other investigated flavor compounds stored at 25 degrees C were greater than those of the ones stored at 20 or 30 degrees C.