Coconut Liquid Endosperm Research Articles

Efficacy of coconut liquid endosperm as natural agent inhibiting browning and maintaining quality of fresh-cut mature mangoes by comparison with cysteine

The use of natural substances to preserve the freshness of fresh-cut products has been receiving a lot of attention recently. The aim of the present work was to determine the efficacy of coconut liquid endosperm (CLE) immersion on browning retardation and quality maintenance of fresh-cut mature green mangoes by using ‘Kaew Kamin’ mango as fresh-cut fruit model compared with cysteine (Cys) immersion during refrigeration at 4°C. In the preliminary investigation, the treatment of CLE or Cys retarded the colour change ( hue angle) and browning development during refrigeration. The optimal concentrations of CLE and Cys were 100 and 1.5%, respectively. Compared with untreated samples (100% CLE), 1.5% Cys and Cys + CLE immersions maintained firmness, superficial colour, and visual appearance, as well as inhibited the browning and polyphenol oxidase (PPO) activity of the fresh-cut mangoes. Interestingly, Cys immersion enhanced antioxidant activity and the total phenolic compounds of the fresh-cut mangoes. The total phenolic content of the fresh-cut mangoes was unaffected by CLE immersion. Compared to Cys, CLE is a natural substance that prevents browning, and maintains the freshness of fresh-cut mature green mangoes throughout refrigeration.

Effects of indole butyric acid and coconut liquid endosperm on rooting of Crateva adansonii stem

Indole butyric acid (IBA) and coconut liquid endosperm (CLE), two rooting agents, were tested in three concentrations to see how they affected the rooting of Crateva adansonii DC stem cuttings. 300 mg/L, 200 mg/L, and 100 mg/L (IBA) of rooting material and 100%, 80%, and 60% of CLE were the concentrations that were assessed. This was done in three replications using completely randomized design (CRD). The setup, which lasted six months, was on exhibit in the Botanic Garden at the Department of Plant Science and Biotechnology, University of Nigeria, Nsukka. While control stem cuttings took the longest to start and finish bud break on the stem cuttings, higher concentrations of the rooting chemical substances, 300 mg/L IBA and 100 percent CLE respectively, influenced the shortest times (initial and final). The results showed that the control had the fewest buds that sprouted into leaves, whereas 300 mg/L IBA and 100 percent CLE had the highest percentage of buds that turned into leaves on the stem cuttings. Regardless of the treatment concentrations utilized, a thin callus formed on the stem cuttings. Observations on rooting revealed that not all callused stem cuttings subsequently took root. IBA and CLE were applied to stem cuttings in various concentrations, and the results were seedlings with lateral and feeding roots. The maximum percentage of rooting response was seen in stem cuttings treated with 300 mg/L IBA and 100 percent CLE, respectively, while the control did not root. The findings of measuring the aerial and sub aerial growth characteristics of seedlings revealed that 300 mg/L IBA and 100 percent CLE had a greater impact on the development of higher values of the growth parameters examined than cuttings treated with lower concentrations of the two rooting agents. Based on the findings of this study, it is possible to draw the conclusion that C. adansonii can be multiplied vegetatively by using rooting agents to help stem cuttings take root. It is recommended that more research be done using rooting medium with a higher concentration and rooting agents like auxins at different concentrations.

Green synthesis and Characterisation of Silver Nanoparticles from liquid endosperm of Coconut, Palm fruit and Coconut toddy and it’s Antibacterial Activity

Nanoparticles are molecules in the range of 1 nm to 100 nm and they can be synthesized by physical, chemical and biological methods. Green synthesis involves the production of nanoparticles from bacteria, fungi, algae, plants and plant extracts. Plant extracts with their chemical constituents can capture the target metals from their salt solution and transform the metal particles into nanoparticles with the cellular catalysts. The present study focuses on the green synthesis of silver nanoparticles using the liquid endosperm of coconut, the coconut water (Cocos nucifera), Liquid endosperm of palm fruit (Borassus flabellifer) and coconut Toddy as the reducing agent. The bio-reduction of aqueous silver ions by coconut water is identified by its colour change. During the synthesis of silver nanoparticles, the colour of the solution changed from milky white to brown. The characterization of synthesized AgNPs (Silver Nanoparticles) was done by Fourier Transform Infrared Spectroscopy and UV-Vis Spectroscopy. The peaks obtained at 250 and 350 nm confirmed the presence of synthesized Silver Nanoparticles. The antibacterial activity of the synthesized nanoparticles was studied on Escherichia coli, Staphylococcus aureus and Streptococcus pyogenes using disc diffusion method. The recent approach of green synthesis is quite impressive due to its eco- friendly, economical, feasible and non- toxic nature.

Effect of microwave heating on physico-chemical characteristics of coconut water

Coconut water (Cococus Nucifera. L) is the clear liquid present inside a coconut liquid endosperm. This water is subjected to microbial contamination and degrades while exposed to ambient air. In general, thermal methods are mostly used in the preservation of liquid foods. In this study, the coconut water was collected from 8-10 months old harvested coconut. Microwave power levels of 540 W, 720 W, and 900 Whavebeen used to treat the coconut water with different exposure times. The treated coconut water was filled in PET bottles and stored at cool temperature (4 °C) and room temperature (27 °C). It is observed that microwave treated 540 W, 720 W, and 900 W coconut water has maintained the quality during the storage period. The physico-chemical properties of microwave-treated coconut water includecolor, pH, TSS, acidity, and reducing sugar on 15days of storage was measured as 13.18 to 15;5.4 to 4.8; 4.5 to 6.0;0.07 to 0.30; and 1.8 to 3.3% respectively.

Browning inhibition on fresh-cut apple by the immersion of liquid endosperm from mature coconuts.

The application of natural antibrowning agents for fresh-cut products has been recently considered. This study manifested the efficiency of coconut liquid endosperm, coconut water (CW), from mature tall (cooking) coconut (C-CW) and yellow dwarf coconut (Y-CW) on browning inhibition of 'Gala' apple wedges during storage at 4 ± 1°C for 9days. The apple wedges were immersed in water (control), C-CW or Y-CW for 1min. The visual appearance, superficial colour attributes, browning pigment concentration, total phenols concentration, polyphenoloxidase (PPO) activity and reducing antioxidant capacity of apple wedges were monitored. Moreover, antioxidant activity of both C-CW and Y-CW was also observed. Antioxidant activity of Y-CW was higher than that of C-CW. Both of the CW immersions maintained visual appearance, whiteness and lightness values as well as delayed the increased yellowness and brownness values of hypanthium (flesh) and mesocarp (core) of apple wedges. The browning pigment concentration and PPO activity were obviously lowered by both CW immersions. Total phenols concentration and antioxidant activity of C-CW and Y-CW immersed apple wedges were higher than those of control samples. In conclusion, both of the mature coconut liquid endosperms are feasible natural agent inhibiting browning incidence of fresh-cut fruits during storage.

Nutritional assessment study and role of green silver nanoparticles in shelf-life of coconut endosperm to develop as functional food.

Tender coconut water is a pure and nutritious drink which play important role as nutraceuticals and pharmaceuticals contributes to the rapid growth of the functional food industry. In the mean-time the safety and shelf-life of the food is crucial for the both product as well as consumers. The intervention or application of nanotechnology gives immense a solution for the prolonged sustainability of the food products. This work reports on the nature of physiological changes of coconut liquid endosperm along with the interaction of its DNA with green route synthesized Ag nanoparticles (AgNPs) using Garuga pinnata leaf, an important ethnomedicinal plant. The physical and nutritional study of the coconut water were carried by UV–visible, XRD, NMR analysis whereas the synthesized Ag nanoparticles (AgNPs) were characterized by UV–Visible spectrophotometer, Raman Spectroscopy, DLS, AFM and FE-SEM analysis. The pH of the endosperm was found to decrease from 6.31 to 4.01, following an exponential decay trend and giving a decay constant of ~8.8 h. The broad absorption peak at ~310 nm gradually turns featureless with elapse of time. The proton nuclear magnetic resonance (H1-NMR) spectrum essentially revealed the presence of esters or organic acids, confirming a sudden fall in the rate of intensity in the immature coconut endosperms as compared to the matured coconut cases. While the pentosyl methyl group (~1.4–1.5 ppm) concentration is observably lowered, free amino acid (~1 ppm) is apparently suppressed in the former specimen. Gel electrophoresis of 10 kb DNA with Ag nanoparticles (AgNPs) showed a gradual decrease of band intensity for a concentration varying between 3:1 and 1:1. The less intense band was due to the lack of migration of DNA into the micropores of the gel as a consequence of interaction of negatively charged DNA with negatively charged AgNPs. The study of DNA interaction with AgNPs could help identifying and addressing the nature of degradation process while considering prevention from microbial attack and make the coconut water as potential functional food entity.

Prior physicochemical stress exposures and subsequent UV-C resistance of E. coli O157:H7 in coconut liquid endosperm

This study determined the effects of prior exposures to individual acid, desiccation, and heat stress, and all their possible simultaneous combinations, on the subsequent ultraviolet-C (UV-C) inactivation kinetics of E. coli O157:H7 in a coconut liquid endosperm suspending medium. Sublethal injury rates determined in the cells after stress exposure and acclimation in the suspending medium ranged from 0.00% (acid stressed) to 84.24% (desiccation+heat stressed). Regardless of the previous stress to which cells were exposed, a logarithmic linear inactivation behavior was observed in the cells. The decimal reduction energy (DUV-C) of the stressed cells ranged from 152.17mJ/cm2 (acid+desiccation+heat stressed) to 209.81mJ/cm2 (acid+heat stressed). No apparent relationship was observed between % injury and DUV-C values possibly because the nature of the injury the cells incurred after exposures to the stresses was not determined. Cells previously exposed to the combined acid and heat stress exhibited the highest D ratio (DUV-C stressed/ DUV-C control), indicative of heterologous adaptation that resulted in cells 30% more resistant towards UV-C. The results established in this study contribute in further understanding the utility and limitations of UV-C radiation as an alternative nonthermal processing technique for fruit juices.

Decimal reduction energies of UV-C-irradiated spoilage yeasts in coconut liquid endosperm

The ultraviolet-C (UV-C) decimal reduction energy (DUV-C) values of 17 spoilage yeasts and their composited inoculum were determined in coconut liquid endosperm (pH 5.26, 5.8 °Brix, 0.04% malic acid, 0.17% w/v insoluble solids). Growth kinetic parameters of all the test yeast strains were first established to standardize the growth stage of the cells prior to inactivation studies. Approximately 4.0 to 5.0 log CFU/mL cells in the mid-stationary growth phase (30.3 to 39.9 h, 25 °C) were suspended in 4 mL turbulent flowing juice and subjected to UV-C irradiation at a surface irradiance range of 3.42 to 4.99 mW/cm2. Survivor populations after exposure to predetermined UV-C energy were enumerated, and were used to derive the DUV-C values using the linear regression and Baranyi and Roberts (1994) model fitting. Results show that the yeast strains exhibited either log-linear or biphasic inactivation behavior with inactivation lag. The most UV-C resistant spoilage yeast was found to be Cryptococcus albidus (LJY1) with DUV-C values of 122.72 and 214.89 mJ/cm2 determined from linear regression and model-fitting, respectively. The least UV-C resistant was Torulaspora delbrueckii (LYJ5) with a DUV-C of 17.34 (linear regression) and 17.35 mJ/cm2 (model-fitting). The DUV-C values determined from the model fitting were generally greater than those calculated from linear regression, although only those determined for C. albidus were significantly different. To the investigators' knowledge, this is the first report of the UV-C inactivation kinetic parameters of Kluyveromyces marxianus, Trichosporon cutaneum, Pichia anomala, and Meyerozyma guilliermondii and C. albidus in coconut liquid endosperm. The results of this study can be used in the establishment and validation of UV-C process schedules for coconut liquid endosperm and other similar commodities.

Effects of suboptimal growth conditions on the subsequent UV-C resistance of Listeria monocytogenes in coconut liquid endosperm and apple juice

This study determined the ultraviolet-C (UVC) resistance of Listeria monocytogenes in coconut liquid endosperm and apple juice after previous exposures to suboptimal growth conditions. L. monocytogenes 1/2c and 4b strains were individually exposed to gradual acidification (final pH 4.5), desiccation (aw 0.96), heating (40 °C), and all their simultaneous combinations. Results showed that regardless of prior growth conditions and fruit beverage suspending medium, L. monocytogenes exhibited log-linear inactivation behavior. The UV-C energy dose necessary to reduce microbial population by 1 log cycle (DUV-C) varied across growth conditions and between fruit beverages. Regardless of growth condition, L. monocytogenes exhibited greater resistance in apple juice. In coconut liquid endosperm, the greatest UV-C resistance was observed in cells previously exposed to acidification and heat (A+H) (DUV-C 37.32 mJ/cm2), while cells previously exposed to acidification and desiccation (A+D) exhibited the greatest resistance to UV-C in apple juice (DUV-C 726.76 mJ/cm2). L. monocytogenes exhibited least UV-C resistance in coconut when previously exposed to heating (DUV-C 25.40 mJ/cm2), while exposure to A+H resulted in least UV-C resistance when suspended in apple juice (DUV-C 298.81 mJ/cm2). These results suggest that in addition to intrinsic suspending medium properties, implicit microbial physiology also affect the efficacy of UV-C treatment.

Individual and combined efficacies of mild heat and ultraviolet-c radiation against Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes in coconut liquid endosperm

This study determined the inactivation kinetic parameters of selected pathogens in heat, ultraviolet-C and combined heat-UV-C treated coconut liquid endosperm. Separate cocktails of Escherichia coli O157:H7, Salmonella enterica serovars, and Listeria monocytogenes strains were inoculated into coconut liquid endosperm (pH 5.15, TSS 4.4oBx, TA 0.062% malic acid, extinction coefficient (ε) at 254 nm of 0.0154 cm−1) for inactivation studies. Result showed that all organisms generally exhibited a log-linear heat inactivation behavior (R2 0.81–0.99). The E. coli O157:H7 cocktail (D55 = 19.75 min, D57 = 10.79 min, D60 = 3.38 min, and D63 = 0.46 min) was found to be significantly more resistant (P > 0.05) than the tested cocktail of L. monocytogenes (D55 = 11.68 min, D57 = 4.53 min, D60 = 1.82 min and D63 = 0.26 min) and S. enterica cocktail (D55 = 3.08 min, D57 = 2.60 min, D60 = 0.89 min and D63 = 0.25 min). Despite the differences in DT values, computed z values for L. monocytogenes cocktail (5.12 ± 0.43 °C) and E. coli O157:H7 cocktail (4.95 ± 0.12 °C) were not significantly different (P > 0.05), but were both significantly (P < 0.05) lower than that of S. enterica cocktail (7.10 ± 0.15 °C). All test organisms also exhibited a generally log-linear UV-C inactivation behavior (R2 0.90–0.99) with E. coli O157:H7 cocktail (DUV-C = 25.26 mJ/cm2) demonstrating greatest resistance to UV-C than S. enterica (DUV-C = 24.65 mJ/cm2) and L. monocytogenes (DUV-C = 17.30 mJ/cm2) cocktails. The D55 values of each organism cocktail were used to calculate for the 3-log reduction heating process schedules, during which UV-C treatments were simultaneously applied. Lethal rates (F values) calculations in the combined processes revealed that within the 3-log reduction heating processes, co-exposure of UV-C resulted in 5.62 to 6.20 log reductions in the test organism populations. Heating caused 69.3, 97.2, and 67.4% of the reduction in E. coli O157:H7, S. enterica and L. monocytogenes cocktails, respectively. These results can be used as baseline data in the establishment of mild heat treatment in combination with UV-C process schedules for coconut liquid endosperm and other similar products.

Previous stress exposures influence subsequent UV-C resistance of Salmonella enterica in coconut liquid endosperm

This study determined the effects of prior exposures to stresses commonly encountered by cells in food production and processing environments on the subsequent UV-C inactivation rates of Salmonella enterica in coconut liquid endosperm. Seven different strains of S. enterica were separately exposed to individual stresses such as gradual acidification (final pH 4.5), abrupt desiccation (aw 0.96), or heat stress at 40 °C for 24 h, after which the test strains were cocktailed and subjected to UV-C challenge. Cells were also exposed to all possible combinations of the individual stresses and thereafter subjected to UV-C challenge. Cells exposed to all individual and combinations of stresses exhibited 1st order, log-linear inactivation behavior (R2 0.903 to 0.998). Cells previously exposed to singular heat stress had the highest UV-C resistance (DUV-C 43.8 mJ/cm2), while cells exposed to all simultaneous pH, aw, and heat stresses had the least (DUV-C 22.5 mJ/cm2). Heterologous adaptive mechanisms were observed after S. enterica cells were exposed to acid, acid + desiccation, heat, and acid + heat, with individual heat stress exposure resulting in the significantly most UV-C resistant cells. Results obtained in this study provide baseline information on the selection of appropriate challenge organism for establishment of UV-C process schedule for coconut liquid endosperm and similar commodities.

Optimization of Coconut Water Beverage Fermented with Lactobacillus acidophilus

Coconut water is the liquid endosperm of coconut. It is a very nutritious and refreshingly natural beverage but highly perishable. The study aimed to optimize and evaluate the coconut water beverage formulation. A 33 factorial experiment arranged in Central Composite Design with the levels of Lactobacillus acidophilus starter culture (10, 15, 20%), pineapple puree as flavorant (5, 15, 25%) and sugar (10, 20, 30%) as the independent variables was used. The growth pattern of the lactic acid bacteria was monitored for 32 hours following serial dilution and pour plating techniques to determine the fermentation time to produce the beverage. Sensory evaluation was conducted using the 9-point Hedonic scale. Response surface methodology was used to identify the optimum formulation. Microbial growth indicated that 24 hours of incubation at 37°c can produce the fermented beverage. With increased level of Lactobacillus acidophilus starter culture, pineapple puree and sugar, acceptability for the product increased. The optimum formulation has 30% sugar, 20% starter culture and 15% pineapple puree. The product is more nutritious than the unfermented beverage and still acceptable when stored at refrigerated condition for 15 days. Fermentation increased the nutritional values of fresh coconut water.

Comparative resistances of selected spoilage and pathogenic bacteria in ultraviolet-C-treated, turbulent-flowing young coconut liquid endosperm

This study determined and compared the inactivation rates of selected spoilage and pathogenic bacteria in turbulent flowing, UV-C treated liquid endosperm (pH 5.80, 6.10 °Brix) obtained from young (6–9 months) coconut drupes. Inoculation of test organisms significantly altered the UV-C absorbance and transmittance of the liquid endosperm from 0.90 to 1.08 and 12.74%–8.39%, respectively. Inactivation rates were expressed in terms of decimal reduction times (D values), defined as the exposure time necessary to reduce the test organism by 90% or 1-log cycle. Furthermore, the DUV-C values, or the UV-C dose necessary to reduce the organism by 90% were also determined. Results showed that while the D and DUV-C values significantly varied among the spoilage organisms (D = 2.93–5.60 s; DUV-C = 7.63–14.56 mJ/cm2), no significant differences were detected in the inactivation rates of the tested pathogens (D = 3.19–3.76 s; DUV-C = 8.28–9.78 mJ/cm2). The inactivation parameters obtained in this work were close to those previously established in non-turbulent, small volume coconut liquid endosperm, suggesting that for this commodity, stirring may not be necessary to optimize microbial inactivation if UV-C shall be applied to small volumes or thin films. The results established in this work may serve as baseline information in the continuous optimization of UV-C process for coconut liquid endosperm and other similar products, for the maintenance and control of food quality and safety.

Reference organism selection for microwave atmospheric pressure plasma jet treatment of young coconut liquid endosperm

This study identified a reference organism for the establishment of microwave atmospheric pressure plasma jet treatment of young coconut liquid endosperm. Three different, predominant spoilage bacteria were isolated from spoiled liquid endosperm and identified through 16S rDNA sequencing, prior to propagation and eventual challenge studies. Basic Local Alignment Search Tool comparisons revealed that the isolated spoilage bacteria were Klebsiella sp., Staphylococcus sp., and Kluyvera sp (%Identity 97.34–97.82%). The isolates were propagated to mid-stationary growth phase (17 h) and thereafter suspended in liquid endosperm. The inactivation rates of the spoilage isolates in liquid endosperm subjected to plasma jet at 450 and 650 W input power settings were determined and compared to those of pathogens Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes. Inactivation rates of all test organisms at 450 W (2.76–5.98 min) were significantly less (p < 0.05) than those at 650 W (1.86–3.11 min). In both power settings, S. enterica exhibited the significantly (p < 0.05) greatest resistance towards plasma treatment, while Staphylococcus sp. exhibited the least. Heat penetration studies in both power settings revealed that the temperature of the liquid endosperm did not significantly increase and did not reach bactericidal ranges (<30 °C) during plasma jet treatment, hence the observed inactivation were attributed to antimicrobial species generated by the plasma. Optical emission spectroscopy revealed that these antimicrobial species included atomic oxygen (777.41 and 844.67 nm) and ultraviolet radiation (200–280 nm). Thus, this study determined S. enterica as an appropriate target organism for the establishment of plasma jet process for coconut liquid endosperm, the inactivation rate of which shall be soon established in higher scale treatment process.

Antimicrobial peptide (Cn-AMP2) from liquid endosperm of Cocos nucifera forms amyloid-like fibrillar structure.

Cn-AMP2 is an antimicrobial peptide derived from liquid endosperm of coconut (Cocos nucifera). It consists of 11 amino acid residues and predicted to have high propensity for β-sheet formation that disposes this peptide to be amyloidogenic. In the present study, we have examined the amyloidogenic propensities of Cn-AMP2 in silico and then tested the predictions under in vitro conditions. The in silico study revealed that the peptide possesses high amyloidogenic propensity comparable with Aβ. Upon solubilisation and agitation in aqueous buffer, Cn-AMP2 forms visible aggregates that display bathochromic shift in the Congo red absorbance spectra, strong increase in thioflavin T fluorescence and fibrillar morphology under transmission electron microscopy. All these properties are typical of an amyloid fibril derived from various proteins/peptides including Aβ.

Previous physicochemical stress exposures influence subsequent resistance of Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes to ultraviolet-C in coconut liquid endosperm beverage

This study investigated the influences of prior exposures to common physicochemical stresses encountered by microorganisms in food and food processing ecologies such as acidity, desiccation, and their combinations, on their subsequent susceptibility towards UV-C treatment in coconut liquid endosperm beverage. Cocktails of Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes were separately subjected to gradually acidifying environment (final pH4.46), exposed to abrupt desiccation by suspension in saturated NaCl solution (aw=0.85) for 4, 8, and 24h, and sequential acidic and desiccated stresses before suspending in the coconut beverage for UV-C challenge. The exposure times (D) and UV-C energy dose values (DUV-C) necessary to reduce 90% of the population of the different test organisms varied with previous exposures to different sublethal stresses, indicating possible influence of implicit microbial factors towards resistance to UV-C. All tested individual and combined stresses resulted in increased resistance, albeit some were not statistically significant. Non-stressed cells had D values of 3.2–3.5s, and corresponding DUV-C values of 8.4–9.1mJ/cm2. Cells exposed to previous acid stress had D values of 4.1–4.8s and corresponding DUV-C values of 10.7–12.5mJ/cm2. Prior exposure to desiccation resulted in D values of 5.6–7.9s and DUV-C values of 14.7–20.6mJ/cm2, while exposure to combined acid and desiccation stresses resulted in D values of 6.1–8.1s and DUV-C values of 15.9–21.0mJ/cm2. The D and DUV-C values of S. enterica after previous exposure to sequential acid (24h) and desiccation (24h) stresses were found significantly greatest, making the organism and physiological state an appropriate reference organism for the establishment of UV-C pasteurization process for the beverage.

Assessment of volatile and non-volatile organic compounds in the liquid endosperm of young ‘Nam Hom’ coconut (Cocos nucifera L.) at two stages of maturity

SUMMARYYoung coconut (Cocos nucifera L.) fruit collected 6–8 months after anthesis (MAA) contain a high volume of water [20% (w/w)] and can provide a refreshing drink. The present study investigated volatile organic compounds (VOCs), as aroma components, and physico-chemical changes in the liquid endosperm of young ‘Nam Hom’ coconut at two stages of maturity: the one-layer stage (6 MAA) and the two-layer stage (7.0–7.5 MAA) of the flesh. The liquid endosperm of coconut fruit becomes sweeter and more turbid late during maturation. Lauric acid (C12:0) and myristic acid (C14:0) were the main free fatty acids in the liquid endosperm of coconut. Short-chain fatty acid (C10–C12) concentrations increased slightly, and longer-chain fatty acid (C14–C18) concentrations declined when fruit matured from the one- to the two-layer stage of flesh. Solvent extractions showed a 1.4-fold increase in the total concentration of VOCs in the liquid endosperm during fruit development. This was related to a major increase in squalene and sterols, to 21.7% (w/w) of the total VOC and non-volatile organic compounds, whereas the concentrations of terpenes and esters remained stable. Although a series of alkanes existed in the liquid endosperm of coconut, the main aroma components were 2-methyl-1-butyl acetate and terpenes such as D-limonene, α-pinene, and 3-carene. We conclude that, when coconut fruit developed from the one- to the two-layered flesh stage, the liquid endosperm not only became sweeter and contained higher concentrations of aroma volatile and non-volatile components, but also became oily and less translucent.

Application of ultraviolet-C radiation to inactivate acid-and-desiccation stressed Salmonella enterica in young and mature coconut liquid endosperm mix beverage

The occurrences of outbreaks of infections due to consumption of unpasteurized fruit beverages, and the negative effects of heat treatment towards quality are features of the consumer demand paradox on safety and quality that the industry has to address. This study established the efficacy of ultraviolet-C (UV-C) treatment against acid-and-desiccation stressed Salmonella enterica; and applied and evaluated a process schedule with a recommended lethal rate of 99.999% against the target pathogen. Determinations of decimal reduction times revealed that suspension volume and flow property significantly affected inactivation of the test organism, which exhibited the greatest resistance to UV-C when suspended in 500 ml, non-agitated coconut beverage. A UV-C process schedule with a level of lethality of 5-log cycle reduction against the reference organism was then applied to the beverage. Quality evaluations showed that the pasteurization process resulted in significant color changes in the beverage. The process also significantly affected the microbiology of the beverage, but the population of spoilage microorganisms continuously increased during storage; surpassing microbial limits by the 2nd d of refrigerated storage. The sensory quality scores of the processed beverage were not significantly different from the non-processed control, and were higher than an established commercial brand.

Influences of malic acid and nisin supplementations on the decimal reduction times of Escherichia coli O157:H7 in mildly-heated young coconut liquid endosperm

This study was conducted to determine the effects of malic acid (800–1500 ppm) and nisin (0–150 ppm) on the heat resistance of Escherichia coli O157:H7 in young coconut liquid endosperm. The Central Composite Rotatable Design was applied to determine the various combinations of the two supplements to be added to young coconut liquid endosperm. The lowest D55 value was observed in the combination of 1500 ppm malic acid and 75 ppm nisin at 14.89 ± 4.17 min, while highest was 27.04 ± 4.98 min in the combination of 1150 ppm malic acid and 75 ppm nisin. The D55 values established from the combinations tested did not significantly vary, indicating that within the ranges of supplementation tested, significant influences of both additives and their interaction on the heat resistance of the pathogen did not exist. It was however emphasized that all supplementation combinations resulted in D55 values significantly lower than that in the unsupplemented medium, reducing the heat resistance of the cells by as much as 3-folds. Therefore, thermal processes to be established in the supplemented liquid endosperm shall be less severe, and may be applied to preserve sensory attributes.

Evaluation of sodium benzoate and licorice (Glycyrrhiza glabra ) root extract as heat-sensitizing additives against Escherichia coli O157:H7 in mildly heated young coconut liquid endosperm

This study evaluated the use of sodium benzoate (SB) and licorice root extract (LRE) as heat-sensitizing additives against Escherichia coli O157:H7 in mildly heated young coconut liquid endosperm. Consumer acceptance scoring showed that maximum permissible supplementation (MPS) levels for SB and LRE were at 300 and 250ppm, respectively. The MPS values were considered in the generation of a 2-factor rotatable central composite design for the tested SB and LRE concentration combinations. Liquid endosperm with various SB and LRE supplementation combinations was inoculated with E.coli O157:H7 and heated to 55°C. The susceptibility of the cells towards heating was expressed in terms of the decimal reduction time (D55 ). Response surface analysis showed that only the individual linear effect of benzoate significantly influenced D55 value, where increasing supplementation level resulted in increasing susceptibility. The results reported could serve as baseline information in further investigating other additives that could be used as heat-sensitizing agents against pathogens in heat-labile food systems. Fruit juice products have been linked to outbreaks of microbial infection, where unpasteurized products were proven vectors of diseases. Processors often opt not to apply heat process to juice products as the preservation technique often compromises the sensorial quality. This work evaluated two common additives for their heat-sensitizing effects against E.coli O157:H7 in coconut liquid endosperm, the results of which may serve as baseline information to small- and medium-scale processors, and researchers in the establishment of mild heat process schedule for the test commodity and other similar products.