Interaction of Low Molecular Weight Phenolics with Proteins (BSA)

Mixtures of bovine serum albumin (BSA) and several low molecular weight phenolics were incubated and fractionated using G-50 Sephadex chromatography. Fractions corresponding to the protein and the possible phenolic-protein complexes and fractions corresponding to the free phenolics were collected, and their phenolic content was determined. Among the selected commercial phenolic standards tested ( p -coumaric acid, p -hydroxybenzoic acid, protocatechuic acid, caffeic acid and (+)-catechin), the strongest BSA-binding affinity was demonstrated by 3,4-dihydroxy benzoic and cinnamic acids (protocatechuic acid and caffeic acid), whereas p -hydroxybenzoic acid did not interact with BSA. The methodology was also applied to a phenolic extract obtained from lentils containing p -coumaric acid, a p -coumaric acid derivative, (+)-catechin and procyanidins B₃ [(+)-catechin-(4αÕ8)-(+)-catechin] and B₁ [(-)-epicatechin-(4αÕ8)-(+)-catechin]. Interactions observed among the lentil phenolics and BSA were comparable to those observed among the commercial phenolic standards and BSA.     

Specificity in Thermal Hydrolysis of Triglycerides

SUMMARY— Samples of triglycerides and triglyceride mixtures were heated in the presence of water under controlled conditions and the released fatty acids quantitatively analyzed by gas chromatography. Experiments with both a mixture of monoacyl-triglycerides and glycerides with equimolar amounts of randomly distributed fatty acids showed a preference for the hydrolysis of the shorter chain and the unsaturated fatty acids. The C₄, C₈, C₁₂, and C_18:1, fatty acids were used in the above mixtures. A trilaurin, in which the fatty acid in the P-position is labelled with C¹⁴, was synthesized. When the free acids released by heat were analyzed by a combination gas chromatographic-radioactivity detector system, no evidence for a positional specificity was apparent.     

Study on cholesteryl ester fatty acids in camel and cow milk lipid

Summary The average lipid content of mature camel milk (3.48 g100g⁻¹), was found to be less than cow's milk (3.69g 100g⁻¹), but the total cholesterol content of camel milk was high (31.32 mg100g⁻¹) when compared to the total cholesterol content of cow's milk (25.63mg100g⁻¹). The average free cholesterol content of mature milk from 54 lactating camels was 21.34 mg100g⁻¹, while the average free cholesterol of mature milk of 24 lactating cows was 17.25 mg100g⁻¹. In the esterified fraction of camel's milk the percentage of saturated fatty acids was 52% with a content of palmitic acid of 18.4%. In cow's milk saturated fatty acids accounted for 58% of the total with a content of palmitic acid of 23.6%. The unsaturated fatty acids fraction in both groups was mainly contributed by oleic acid and palmitoleic acid. Pelargonic acid (C9:0) and decanoic acid (C10:1) were found in significant amounts in mature camel milk, but were only just detectable in cow's milk. The higher content of medium chain fatty acids in camel milk is useful from a nutritional point of view as they are more easily absorbed and metabolized than long chain fatty acids.     

Influence of Storage Temperature on the Kinetics of the Changes in Anthocyanins, Vitamin C, and Antioxidant Capacity in Fresh-Cut Strawberries Stored under High-Oxygen Atmospheres

ABSTRACT:  Changes in the main antioxidant properties of fresh-cut strawberries stored under high-oxygen atmospheres (80 kPa O₂) were studied at selected temperatures (5 to 20 °C). The suitability of zero- and 1st-order kinetics as well as a model based on Weibull distribution function to describe changes in experimental data is discussed. A non-Arrhenius approach was used to determine the temperature dependence of the estimated rate constants. A Weibull kinetic model most accurately  ( R ²_adj≥ 0.800)  estimated changes in anthocyanins and antioxidant capacity of fresh-cut strawberries throughout the storage period, whereas a 1st-order model adequately fitted  ( R ²_adj≥ 0.982)  the variation of vitamin C. The temperature dependency of the kinetic rate constants for each antioxidant property was successfully modeled through the non-Arrhenius approach  ( R ²_adj≥ 0.709)  . The T_c obtained for anthocyanins, vitamin C, and antioxidant capacity degradation were 290, 284, and 289 K, respectively, indicating the temperature at which a marked acceleration of the losses in the antioxidant potential of strawberry wedges occurs. These findings will help to describe the variation of the antioxidant potential of fresh-cut strawberries upon storage time and temperature.     

Canarium zeylanicum seed oil: an edible oil with beneficial qualities

The quality parameters, fatty acid composition, phenolic compounds and antioxidant properties of the seed oil of Canarium zeylanicum were determined. The results indicate that the seed oil of Canarium zeylanicum is an excellent source of essential fatty acids which contains C18:2 (49.35 ± 0.35%) and C18:3 (19.09 ± 0.01%). The total phenol contents of the seed oil and the seed hull of Canarium zeylanicum were 66 ± 6 and 2014 ± 14 mg kg⁻¹respectively. The identified phenolic acids in the methanolic extracts of seed oil include 3,4-dihydroxybenzoic acid, p -hydroxybenzoic acid, vanillic acid and ellagic acid. Diphenyl-2-picrylhydrasyl radical scavenging activity, inhibition of deoxyribose degradation and the reducing power of the methanolic extracts of seed oil and seed hull of Canarium zeylanicum are comparable with those of butylated hydroxytoluene solutions.     

Efficacy of pulsed UV-light for the decontamination of Escherichia coli O157:H7 and Salmonella spp. on raspberries and strawberries

ABSTRACT:  Small fruits are increasingly being implicated in outbreaks of foodborne illness, and fresh produce is now the 2nd leading cause of foodborne illness in the United States. Conventional methods of decontamination are not effective, and there is a need to evaluate novel technologies. Pulsed ultraviolet (UV)-light is one such technology. In this study, pulsed UV-light was applied to strawberries and raspberries at varying UV doses and times. On raspberries, maximum reductions of Escherichia coli O157:H7 and Salmonella were 3.9 and 3.4 log₁₀ CFU/g at 72 and 59.2 J/cm², respectively. On the surfaces of strawberries, maximum reductions were 2.1 and 2.8 log₁₀ CFU/g at 25.7 and 34.2 J/cm², respectively. There was no observable damage to the fruits at these UV doses. The results obtained in this study indicate that pulsed UV-light has the potential to be used as a decontamination method for raspberries and strawberries.     

EFFECT OF VITAMIN E SUPPLEMENTATION ON INTRA- AND INTERMUSCULAR FATTY ACID COMPOSITION OF AWASSI LAMBS

This research was carried out to determine the effects of vitamin E supplementation on inter- and intramuscular fatty acid composition in meat of Awassi lambs. Lambs were divided into two groups, control (CG) and experimental (VG), at the beginning of the fattening period. The CG and VG lambs were fed the same concentrate and hay. The VG also received a supplement of 45 mg vitamin E (DL-α tocopheryl acetate) per lamb per day for the 75-day fattening period prior to slaughter. After slaughtering, carcasses were stored at 4 0.5C for 24 h. Then , M. longissimus dorsi (LD) muscles were excised from carcasses, and the intra- and intermuscular fats from LD muscles were used as study material. Results showed that vitamin E supplementation had no significant effect on fatty acid composition in intra- and intermuscular fats (P < 0.05). Fatty acid content in intramuscular fats were different than those in intermuscular fats (P < 0.01) except for lauric (C₁₂), linoleic (C_18:2) and linolenic (C_18:3) acids (P < 0.05). Total saturated fatty acids in the intramuscular fats were lower than in intramuscular fats (P < 0.01). In addition, the majority of fatty acids, both intramuscular and intermuscular, in Awassi lambs were oleic (C_18:1), palmitic (C₁₆ and stearic (C₁₈) acids.     

Modeling of Calcium Chloride and Pectin Methylesterase Prefreezing Treatments of Strawberries and Jams

ABSTRACT: :
Different calcium chloride (CaCl₂) and pectin methylesterase (PME) prefreezing treatments in a vacuum were used to clarify the most effective prefreezing factors for strawberries and traditional jams. Fractional factorial design and modeling were used. CaCl₂ had the greatest effect on the majority of the 15 studied responses ( p < 0.001). The pretreatment time should be short (about 5 to 10 min), the temperature low (less than 20 °C), the vacuum level high (pressure less than 10 kPa), the CaCl₂ concentration moderate (about 1%) and the dosage of PME comparatively low (about 50 to 100 nkat/g) in order to yield high quality frozen strawberries for jam making.     

Vacuum Impregnation Pretreatment with Pectinmethylesterase to Improve Firmness of Pasteurized Fruits

ABSTRACT: Vacuum impregnation allows replacing the occluded air present in fruits by a solution. Apples, strawberries, and raspberries were infused in a solution of pectinmethylesterase (PME) and calcium chloride (CaCl₂) either by using this technology or by classical infusion. The vacuum pretreatment limited the loss in fruits firmness following pasteurization. The influence of PME and CaCl₂concentrations in the vacuum impregnation solutions on the calcium content, the PME activity and the firmness of pretreated strawberries was studied: the firmness of strawberries was maximal after impregnation in solutions containing a threshold concentration of PME and/or calcium. The synergistic action of PME and calcium used in the vacuum impregnation solution was significant.     

FATTY ACIDS FROM LARVAL SULCASCARIS SP. (NEMATODA) AS POSSIBLE INDICATORS OF INFECTION OF CALICO SCALLOPS (ARGOPECTEN GIBBUS)

Fatty acid profiles of larval nematodes (stage- 4 Sulcascaris sp.), of tissue from their intermediate host (calico scallops, Argopecten gibbus), and of the host capsule that surrounds the larvae were prepared in an attempt to identify infected scallops. Nematode tissue showed lower ratios of C_14:O/C_14:1, C_16:0/C_16:1 and C_18:0/C_18:1 than did scallop tissue. The nematodes contained relatively less C_16:0 and more C_18:2 than did scallops. Fatty acids shorter than C_14:0 were found in small amounts in both organisms. Fatty acid profiles of capsules differed little from those of normal scallop tissue.     

The Effectiveness of Sanitizer Treatments in Inactivation of Salmonella spp. from Bell Pepper, Cucumber, and Strawberry

ABSTRACT: Four different postharvest treatments for removal of Salmonella from bell pepper and cucumber were examined, including washes with chlorinated water (HOCl; 200 ppm), acidified sodium chlorite (ASC; 1200 ppm), and peroxyacetic acid (PAA; 75 ppm), and treatment with gaseous chlorine dioxide (ClO₂; total 100 mg). Only ClO₂ gas was evaluated for decontamination of strawberries. Each produce was inoculated with approximately 1.0 × 10⁷ colony-forming units (CFU) of a 5-serovar cocktail of Salmonella on artificially created wounds, smooth surfaces, and stem scar tissue. For tests involving smooth surface inoculation, ASC and PAA treatments decreased contamination to undetectable levels on bell pepper and cucumber, while the chlorine treatment of bell pepper reduced contamination by approximately 2-logs. For stem scar contamination on bell pepper, ASC and PAA treatments both showed >2-log unit reductions, and chlorine treatment showed a <1-log unit reduction. For puncture wounds on bell pepper, HOCl, ASC, and PAA treatments reduced bacterial levels approximately 2-, 3-, and 1-log units, respectively, indicating that HOCl and ASC were more effective than PAA. These aqueous treatments of cucumber with puncture wounds reduced bacterial levels approximately 1-, 2-, and 2-log units, respectively. ClO₂ treatment decreased counts to undetectable levels on all inoculation sites on cucumber and on strawberry smooth surfaces, but failed to completely eliminate Salmonella from bell pepper and from the stem scar and the puncture wounds of strawberry. ASC treatment of bell pepper and ClO₂ gas treatments of cucumber showed the best efficiency for inactivation of Salmonella. ClO₂ treatments effectively reduced Salmonella cells inoculated on the smooth surface and stem scar of strawberries compared with unsanitized control.     

INHIBITION OF MICROORGANISMS IN SALAD DRESSING BY SUCROSE AND METHYLGLUCOSE FATTY ACID MONOESTERS

The antimicrobial activity of sucrose and methylglucose esters of medium to long chain fatty acids was studied with two microorganisms involved in the spoilage of salad dressings, Zygosaccharomyces bailii and Lactobacillus fructivorans. The microorganisms were inhibited to various degrees by 0.1, 0.5, and 1.0% synthesized sucrose or methylglucose monoesters using a modified broth dilution method. Sucrose monoesters were most inhibitory when the esterified fatty acid was myristic (C₁₄) or palmitic acid (C₁₆). Methylglucose monoesters with lauric (C₁₂) or myristic acid (C₁₄) exhibited greater inhibition than those with longer chain fatty acids. The least inhibition was generally observed with sucrose and methylglucose oleate (C_18:1). Sucrose monoesters were usually more inhibitory than methylglucose monoesters of the same fatty acid, especially for palmitic and stearic (C₁₈) acids. In salad dressing, 1% sucrose monoesters of lauric, myristic, or palmitic acid significantly (P < 0.05) inhibited the growth of Z. bailii and L. fructivorans, and were comparable with or more effective than 0.1% sodium benzoate. Z. bailii growth was nearly completely inhibited by sucrose laurate, myristate and palmitate by 9 days of salad dressing storage. Sucrose monoesters did not delay the lag phase of L.     

Fruit Quality, Antioxidant Contents and Activity, and Antiproliferative Activity of Strawberry Fruit Stored in Elevated CO2 Atmospheres

ABSTRACT:  The effects of CO₂ in the storage atmosphere on color, firmness, ascorbic acid (AA), anthocyanins, flavonoids, phenolics, total antioxidant activity, and antiproliferative activity of strawberry fruit have been investigated. "Northeaster" and "Earliglow" strawberries were stored in air or in 20% CO₂ (in air) at 3 °C for 20 d. Color changes in Northeaster were delayed more by CO₂ treatment than in Earliglow. Firmness of CO₂-stored fruit increased slightly compared with those stored in air. The increases in total and reduced AA concentrations during air storage were usually prevented by CO₂ storage in both cultivars. Dehydroascorbic acid (DHA) concentrations increased during CO₂ storage. Anthocyanins and flavonoids, and total antioxidant activity of both cultivars were higher in air-stored fruit than in CO₂-stored fruit. The total phenolic concentration was lower in CO₂-stored Earliglow fruit than in air, but storage treatment did not affect that of Northeaster. A 40 mg/mL concentration of Northeaster strawberry extract inhibited about 80% of HepG₂ human liver cancer cell proliferation. CO₂ treatment did not affect the antiproliferative activity of strawberry fruits, but antiproliferative activity was greater at harvest than after storage.     

SIMULTANEOUS DIFFUSION of CITRIC ACID and ASCORBIC ACID IN PREPEELED POTATOES

The study of the simultaneous diffusion of chemical preservatives in vegetable tissues permits the determination of the time required to complete this process and the concentration distributions of the preservatives.
The individual or simultaneous diffusion of citric and ascorbic acids in pre-peeled potatoes was analyzed; the effect of pH decrease on the diffusive flux of ascorbic acid and the interaction between both acids was considered as the multicomponent diffusion problem.
Potato spheres of different radii were immersed in individual solutions or mixtures of citric and ascorbic acids in concentration ranging from 0.5% to 2% W/V for different immersion times and agitation conditions. the residual concentration of citric acid was determined by titrable acidity (22058 AOAC method) and that of ascorbic acid by 2–6 dichlorophenol-indophenol method.
Experimental data were fitted to the mathematical models and the effective diffusion coefficients were determined for citric (D_e= 4.3 ± 0.2 × 10⁻¹⁰ m²/s) and ascorbic acids (D_e= 5.45 ± 0.4 × 10⁻¹⁰ m²/s) diffusing individually. When mixtures of two acids were used, multicomponent analysis was adopted and interaction coefficients were evaluated (D₁₂= 6.67 ± 0.8 × 10⁻¹¹ m²/s and D₂₁= 8.33 ± 0.8 × 10⁻¹¹ m²/s); they were an order of magnitude lower than binary diffusion values.
The pH effect on the diffusive flux of ascorbic acid was decoupled from the interaction of both acids during simultaneous diffusion by studying the diffusion of the first acid in potatoes preacidified with the second acid.     

Antimicrobial effect of electrolyzed oxidizing water against Escherichia coli O157:H7 and Listeria monocytogenes on fresh strawberries (Fragaria x ananassa)

ABSTRACT:  Antibacterial activity of electrolyzed oxidizing (EO) water prepared from 0.05% or 0.10% (w/v) sodium chloride (NaCl) solutions against indigenous bacteria associated with fresh strawberries ( Fragaria × ananassa ) was evaluated. The efficacy of EO water and sodium hypochlorite (NaOCl) solution in eliminating and controlling the growth of Listeria monocytogenes and Escherichia coli O157:H7 inoculated onto strawberries stored at 4 ± 1 °C up to 15 d was investigated at exposure time of 1, 5, or 10 min. Posttreatment neutralization of fruit surfaces was also determined. More than 2 log₁₀ CFU/g reductions of aerobic mesophiles were obtained in fruits washed for 10 or 15 min in EO water prepared from 0.10% (w/v) NaCl solution. Bactericidal activity of the disinfectants against L. monocytogenes and E. coli O157:H7 was not affected by posttreatment neutralization, and increasing exposure time did not significantly increase the antibacterial efficacy against both pathogens. While washing fruit surfaces with distilled water resulted in 1.90 and 1.27 log₁₀ CFU/mL of rinse fluid reduction of L. monocytogenes and E. coli O157:H7, respectively, ≥ 2.60 log₁₀ CFU/mL of rinse fluid reduction of L. monocytogenes and up to 2.35 and 3.12 log₁₀ CFU/mL of rinse fluid reduction of E. coli O157:H7 were observed on fruit surfaces washed with EO water and NaOCl solution, respectively. Listeria monocytogenes and E. coli O157:H7 populations decreased over storage regardless of prior treatment. However, EO water and aqueous NaOCl did not show higher antimicrobial potential than water treatment during refrigeration storage.     

p-HYDROXYPHENYLPROPIONIC ACID (PHPPA) AND 3,4-DIHYDROXYPHENYLPROPIONIC ACID (3,4-DPPA) AS SUBSTRATES FOR MUSHROOM TYROSINASE

p-Hydroxyphenylpropionic acid (PHPPA) and 3,4- dihydroxyphenylpropionic acid (3,4-DPPA) serve as substrates for tyrosinase. The Km value of 3,4-DPPA for tyrosinase is 1.3 mM. The yellow o-quinone of 3,4-DPPA (4-carboxyethyl-o-benzoquinone) (λ_max= 400nm), is detected initially and it is then converted to a red product(s) (λ_max= 480±10 nm), the o-quinone of 6,7-dihydroxy 3-dihydrocumarin (dihydroesculetin). When the concentration of the latter is relatively high, it polymerizes to a final brown product(s), characterized by an ill-defined spectrum.
H₂O₂ shortens the lag period of PHPPA hydroxylation, hastens the conversion of the yellow o-quinone of 3,4-DPPA to the red o-quinone of dihydroesculetin, and prevents the polymerization of the latter to the final brown product(s).
The relatively unstable o-quinone of 3,4-DPPA interacts with amines such as hydroxylamine (NH₂OH), p-aminosalicylic acid (PASA) and p-aminobenzoic acid (PABA), forming relatively stable final product(s) characterized by different spectra from those formed in their absence.
Acetohydroxamic acid (AHA) and salicylhydroxamic acid (SHAM) each has an effect on the spectrum of product(s) obtained when 3,4-DPPA is oxidized by tyrosinase, indicating that these hydroxamic acids derivatives interact with the o-quinone of 3,4-DPPA. The spectrum of the final product(s) was also different when 3,4-DPPA was oxidized by tyrosinase in the presence of benzenesulfinic acid than in its absence, suggesting the formation of a stable phenylsulfonyl derivative.     

Effects of Calcium Chloride-based Prefreezing Treatments on the Quality Factors of Strawberry Jams

ABSTRACT: Vitamin C contents of pretreated strawberries did not change during 2 mo of freezing, but after jam cooking and storage, the vitamin C contents of all the studied jams decreased dramatically. Jams made from strawberries treated with CaCl₂ and PME in a vacuum had the highest firmness compared to the reference or other pretreated jam strawberries (p < 0.05). According to sensory evaluation of the jams, different prefreezing treatments were shown to have a significant influence on the sensory attributes evaluated (p < 0.001), the only exception being the redness of color after 4 mo storage.     

Comparison of six methylation methods for analysis of the fatty acid composition of albacore lipid

Six methods widely used to produce methyl esters for the gas chromatographic determination of the fatty acid composition of a marine lipid were compared. Four acid-catalyzed methods (1% H₂SO₄: CH₃OH; 5% HCl: CH₃OH; 7% and 14% BF₃: CH₃OH) and two base-catalyzed methods [0.5M NaOCH₃: CH₃OH; (1:4) tetramethylguanidine: CH₃OH] were used.
The use of BF₃: CH₃OH (7% and 14%) gave a lower content of 18:1 n9 than the other methods and produced an artefact (2.7–3.2% of total fatty acid content) eluting between the 20:5 and 24:1 fatty acid methyl esters. No significant differences were obtained between the other four methods.
Accordingly the use of BF₃: CH₃OH for transmethylation of marine lipids is not recommended. Results obtained in the other four methods showed that all are comparable.     

A chemical basis for sour taste perception of acid solutions and fresh-pack dill pickles

ABSTRACT:  Sour taste is influenced by pH and acids present in foods. It is not currently possible, however, to accurately predict and modify sour taste intensity in foods containing organic acids. The objective of this study was to investigate the roles of protonated (undissociated) organic acid species and hydrogen ions in evoking sour taste. Sour taste intensity increased linearly with hydrogen ion concentration ( R ²= 0.995), and with the concentration of protonated organic acid species at pH 3.5 ( R ²= 0.884), 4.0 ( R ²= 0.929), and 4.5 ( R ²= 0.975). The structures of organic acid molecules did not affect sour taste after adjusting for the effects of protonated organic acid species and hydrogen ions. Sour taste intensity was also linearly related to the total concentration of protonated organic acid species in fresh-pack dill pickles ( R ²= 0.957). This study showed that the sour taste of organic acids was directly related to the number of molecules with at least 1 protonated carboxyl group plus the hydrogen ions in solution. Conclusions from these results are that all protonated organic acids are equally sour on a molar basis, that all protonated species of a given organic acid are equally sour, and that hydrogen ions and protonated organic acids are approximately equal in sour taste on a molar basis. This study provides a new understanding of the chemical species that are able to elicit sour taste and reveals a basis for predicting sour taste intensity in the formulation of acidified foods.     

Polyphenolic Compounds in Canned Tomato Pastes

SUMMARY– Polyphenolic compounds in canned pastes made from W-14.5 tomatoes ( Lycopersicum esculentum , Mill) were extracted with methanol and ethyl acetate. The compounds. were separated by two-dimensional paper chromatography with n-butanol-acetic acid-water (4:1:5 v/v) and 2% acetic acid as solvents. Twelve spots were found when the chromogenic reagent was FeCl₃K₃Fe(CN)₆. The individual compounds were identified by their R, values and color reactions with Fecl₃K₃Fe(CN)₆, diazotized paranitroaniline, Hoepfner, sodium borohydride, and vanillin-HCI reagents, fluorescent behavior, and absorption spectra. Present in the extracts of tomato pastes were two chlorogenic acid isomers, two caffeic acid derivatives, rutin, naringenin, caffeic acid, and ferulic acid. Naringenin and trans-chlorogenic acid were present in larger amounts than the other polyphenolic compounds.