Addition Of Propyl Gallate Research Articles

Propyl gallate and butylated hydroxytoluene influence the accumulation of saturated fatty acids, omega-3 fatty acid and carotenoids in thraustochytrids

Schizochytrium sp. S31 was shown to have potential for production of the functional food ingredients docosahexaenoic acid (DHA) and astaxanthin, with coproduction of biodiesel. Biomass and lipid levels were greater with glycerol than with glucose as carbon source. Addition of propyl gallate or butylated hydroxytoluene to the media resulted in increased biomass and lipid levels, with propyl gallate being the more effective of the two antioxidants. Medium supplementation with propyl gallate at 0.03% and glycerol as the carbon source resulted in enhanced biomass productivity (28.50 g L−1), lipid accumulation (24.87 g L−1) and astaxanthin levels (452.26 µg L−1).

Interplay between non-photochemical plastoquinone reduction and re-oxidation in pre-illuminated Chlamydomonas reinhardtii: a chlorophyll fluorescence study

In photosynthetic eukaryotes, the redox state of the plastoquinone (PQ) pool is an important sensor for mechanisms that regulate the photosynthetic electron transport. In higher plants, a multimeric nicotinamide adenine dinucleotide (phosphate) (NAD(P))H dehydrogenase (NDH) complex and a plastid terminal oxidase (PTOX) are involved in PQ redox homeostasis in the dark. We recently demonstrated that in the microalgae Chlamydomonas reinhardtii, which lacks the multimeric NDH complex of higher plants, non-photochemical PQ reduction is mediated by a monomeric type-II NDH (Nda2). In this study, we further explore the nature and the importance of non-photochemical PQ reduction and oxidation in relation to redox homeostasis in this alga by recording the 'dark' chlorophyll fluorescence transients of pre-illuminated algal samples. From the observation that this fluorescence transient is modified by addition of propyl gallate, a known inhibitor of PTOX, and in a Nda2-deficient strain we conclude that it reflects post-illumination changes in the redox state of PQ resulting from simultaneous PTOX and Nda2 activity. We show that the post-illumination fluorescence transient can be used to monitor changes in the relative rates of the non-photochemical PQ reduction and reoxidation in response to different physiological situations. We study this fluorescence transient in algae acclimated to high light and in a mutant deficient in mitochondrial respiration. Some of our observations indicate that the chlororespiratory pathway participates in redox homeostasis in C. reinhardtii.

Effects of fish oil type, lipid antioxidants and presence of rapeseed oil on oxidative flavour stability of fish oil enriched milk

AbstractAs a part of our ongoing experiments on optimization of the oxidative stability of fish oils in genuine food systems, this study investigated the oxidative deterioration of fish oil enriched milk emulsions during cold storage. The experimental data showed that addition of rapeseed oil to fish oil (1:1) prior to emulsification into milk significantly protected the emulsions against oxidative deterioration. Addition of propyl gallate and a citric acid ester to the fish oil prior to emulsification also protected the fish oil enriched milk during storage. Emulsions containing a rapeseed:fish oil mixture were oxidatively stable during 11 d at 2 °C. Thus, no additional inhibitory effect of the added antioxidants was observed. The peroxide value and concentrations of five selected volatiles derived from n‐3 PUFA degradation in rapeseed:fish oil mixture emulsions were not significantly different from the corresponding levels in neither the emulsion containing only rapeseed oil nor the milk. It is proposed that the tocopherols in rapeseed oil may be the protective factor. Three‐way chemometric exploratory data analysis was implemented in form of a parallel factor analysis (PARAFAC). The PARAFAC model provided an overview of the obtained data with significantly enhanced interpretability, and revealed information about groupings and correlations in our data.

Chemical and Functional Properties of Oxidatively Modified Beef Heart Surimi Stored at 2 °C

ABSTRACT:Beef heart surimi was prepared using 4 washing conditions: (1) sodium phosphate buffer alone, (2) buffer 1 NaCl, (3) buffer 1 propyl gallate, and (4) buffer 1 sodium tripolyphosphate. Surimi samples were stored at 2 8C and analyzed periodically for protein oxidation, emulsifying properties, and dynamic gelling characteristics. Degree of oxidation differed among washing treatments. Addition of propyl gallate and sodium tripolyphosphate inhibited lipid oxidation but did not prevent protein oxidation. Gel elasticity increased and emulsifying activity decreased for all surimi samples during storage, coinciding with myosin aggregation. Modification of beef heart surimi functionality can be achieved through different washing processes.

Oxidation in fish-oil-enriched mayonnaise

A number of different analytical techniques (HPLC, GC-MS, sensory analysis, laser diffraction droplet size determination, confocal laser scanning microscopy and rheological measurements) were employed to elucidate both chemical, sensory, structural and rheological aspects of the oxidation process in mayonnaise containing 16% fish oil. The primary focus of the study was on the antioxidative effect of two different types of commercial propyl gallate mixtures: an oil-soluble and a water-soluble preparation. The effect of adding extra emulsifier (Panodan TR), used to manipulate the physical structure of the fish-oil-enriched mayonnaise and in turn affect the antioxidative activity of the propyl gallate mixtures, was also investigated. Mayonnaise with fish oil did not oxidise faster than mayonnaise without fish oil when judged from the chemical parameters tested. However, the fish-oil-enriched mayonnaises developed unpleasant off-odours and off-flavours much faster than the mayonnaise without fish oil. Addition of the two different propyl gallate mixtures not only influenced negatively the sensory qualities but also affected the structure and the rheological properties of the mayonnaise. Propyl gallate thus, in particular, promoted the development of fishy and rancid off-flavours during the storage of mayonnaise with fish oil, and this effect was especially pronounced for the water-soluble propyl gallate mixture. Four volatile oxidation compounds, namely 3-furaldehyde, 2,4-heptadienal, 2,4-decadienal and ethyl benzene, appeared to correlate to the fishy and rancid off-flavours that developed in mayonnaises with propyl gallate. Addition of propyl gallate also resulted in increased peroxide values, and a less viscous mayonnaise with bigger droplets. The data thus demonstrated that the propyl gallate mixtures employed did not protect mayonnaise with fish oil against flavour deterioration due to oxidation during storage. In addition, the data showed that several structural and rheological parameters were affected by the addition of propyl gallate.

The effects of low molecular weight additives on the viscosities of cassava starch

The influence of a range of additives on the change in the viscosity of cassava starch pastes on ageing following gelatinisation has been investigated. The inclusion of sulfite with pasted starch markedly decreases the viscosity of the paste with time and this is prevented by the addition of propyl gallate. Intrinsic viscosity measurements strongly support the view that sulfite addition promotes polysaccharide degradation. Ascorbate has a greater degradative effect than sulfite, whereas only limited degradation is observed with glutathione. Salts such as sodium chloride and sodium sulfate show no effect on viscosity. If the chelating agent EDTA is added as well as sulfite, the reduction in viscosity is smaller, although the effect is not cancelled out completely. Interestingly, the degradative effect of sulfite and ascorbate can be shown at 30, 60 and 80° C. The results presented uphold the previous suggestion that sulfite addition promotes oxidative reductive depolymerisation (ORD) and largely rule out any residual enzyme activity as the cause. It is suggested that the strong degradative action of ascorbate on starch could be one of the explanations for its action in baked products.

Sulphite and oxidative—reductive depolymerization reactions

Addition of sulphite at levels between 0.004 and 1% helps to protect the water soluble neutral polysaccharide guar gum from thermal degradation. The greater the amount of sulphite incorporated the more viscous the guar is post-retorting. Starch granules, from a wide range of sources, swell when heated in excess water. The amount of polysaccharide released from the swollen granule after pasting for 60 min at 95 °C is increased by the inclusion of low levels (~0.01%) of sulphite. For cassava starch, a pronounced minimum in swelling volume is observed at this sulphite level. This minimum has been related to the pro-oxidant activity of the sulphite in contrast to the antioxidant activity shown for the guar. Intrinsic viscosity data indicates that the action of the sulphite is to degrade the polysaccharides within the starch granule and this can be reduced by scavenging oxygen from the system or by the addition of propyl gallate. It therefore appears that low levels of sulphite protect guar gum from degradation but can cause degradation of the starch polysaccharides.

Approaches for Improving the Stability of Ketorolac in Powder Blends

Methods for improving the stability of ketorolac powder blends under elevated humidity and temperature conditions were investigated. The approaches that were examined for potentially increasing the stability of ketorolac were varying the ketorolac salt form, altering the excipient ratios, and adding antioxidants or pH modifiers to the formulation. The ketorolac powder blends were stored for 3 months at 75% relative humidity (RH) and 40, 50, and 60 °C. The results showed that the salt form of ketorolac had a large impact on stability after 3 months of storage at 50 °C/75% RH. The calcium salt powder blend and the free acid powder blend exhibited only 0.2% and 0.5% drug loss, respectively, whereas the tromethamine salt powder blend showed a 10.2% drug loss. Varying the ratios of lactose, microcrystalline cellulose, and croscarmellose sodium in the powder blends of ketorolac tromethamine showed that croscarmellose sodium and microcrystalline cellulose destabilized ketorolac. Addition of propyl gallate (1% w:w) to ketorolac tromethamine powder blends increased the stability of the ketorolac significantly. Addition of pH modifiers caused a modest improvement in the stability of ketorolac.

Direct positive inotropic and vasoconstrictor effects of endothelin

Endothelin, a newly discovered vasoconstrictor peptide, when added to isolated cat papillary muscles, induced a direct positive inotropic effect that was slow in onset but of long duration. The magnitude of the developed force was concentration dependent. Endothelin exerted a marked concentration-dependent vasoconstriction in isolated cat carotid arteries and rabbit aortic rings. In both the carotid arteries and the aortic rings, endothelin induced a similar vasoconstrictor effect in the presence or absence of an intact endothelium. Addition of propyl gallate, a 5-lipoxygenase inhibitor, ibuprofen, a cyclooxygenase inhibitor, or SKF-525A, a cytochrome P450 inhibitor, at 2 microM did not significantly attenuate the ability of endothelin to vasoconstrict aortic rings in the presence or absence of an intact endothelium. These results demonstrate that the vasoconstrictor activity of endothelin operates independently of all three pathways of arachidonic acid metabolism (i.e., lipoxygenase, cyclooxygenase, or cytochrome P450 pathways) and is not dependent upon other endothelium-derived mediators (e.g., endothelium-derived relaxing factor, or eicosanoids) in these preparations. Moreover, endothelin exerts a direct positive inotropic effect in isolated cat ventricular myocardial tissue.

Behavior of antioxidants during the baking and storage of pie crust

Summary1. Acidic synergists such as citric acid, phosphoric acid, α‐amino acetic acid (glycine), or disodium dihydrogen ethylenediamine tetraacetate (“Versene”) produced no significant improvement in the keeping quality of pie crust.2. Propyl gallate plus citric acid, or NDGA plus citric acid, produced no significant effect on the keeping quality of pie crust owing to the fact that propyl gallate and NDGA are apparently destroyed in dough made with flour.3. Lauryl gallate plus citric acid produced a significant improvement in the keeping quality of pie crust.4. The addition of “Versene” to dough, followed by spraying the pie crust with a solution of lauryl gallate plus citric acid or propyl gallate plus citric acid, resulted in an increase in stability.5. The addition of BHA plus citric acid to dough resulted in the greatest stability of the pie crust. However the addition of propyl gallate, lauryl gallate or NDGA to this dough produced no further increase in the stability of the pie crust.6. BHA is partly vaporized from dough during the baking process and also during the storage of pie crust at 61°C.

The use of antioxidants in potato chipping

SummaryLaboratory and commercial‐scale fryings of potato chips have been made with various vegetable oils, vegetable shortenings, lard, and combinations of these. Fryings have been made with and without the addition of butylated hydroxyanisole as an antioxidant. The data from both types of experiments indicates that butylated hydroxyanisole possesses “carrythrough” antioxidant properties not only in animal fats but in vegetable oils and vegetable shortenings also. Data also indicates that the addition of propyl gallate and citric acid as synergists to the butylated hydroxyanisole increases the “carry‐through” antioxidant properties.