Peel Samples Research Articles

Removal of Chromium from Waste Water Using Yam Peel Activated Carbon

The paper examined the use of yam peel to develop an adsorbent material with good surface characteristics for the removal of chromium (vi) from waste water. Activated carbons were produced from yam peel under varying conditions; temperature, time and preparation sequence in order to determine the optimum conditions. It's efficiency on the adsorption of chromium from waste water was investigated through batch adsorption studies using direct reading spectrophotometer. Samples of yam peels, 100g each were carbonized under varying temperatures of 100, 200, 300, 400, and 500ºC ,with varying carbonization time of 20, 30, 40, 50 and 60 minutes. The result revealed that 80% of chromium was removed at 200ºC and 40 minutes as the optimum carbonization temperature and time respectively. Effect of preparation sequence was equally evaluated, i.e. raw (powdered form), carbonization without activation, activation with (ZnCL2) before carbonization and activation after carbonization with (ZnCL2) and their adsorbing capacities under an initial concentration of 0.05mg/l were obtained to be 20, 100,100 and 60% respectively. Further increase in concentration results in 100% chromium removal for activation before carbonization and 80% for carbonization without activation. Hence, yam peel activated carbon is recommended for the removal of chromium from wastewater using activation before carbonization procedure at the above optimum conditions.

Simultaneous determination of pyraclostrobin and thiophanate-methyl and its metabolite carbendazim residues in soil and citrus by QuEChERS-liquid chromatography- tandem mass spectrometry

A QuEChERS-liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of pyraclostrobin, thiophanate-methyl and its metabolite carbendazim in soil and citrus. The samples were extracted with methanol or acetonitrile, purified by primary secondary amine (PSA), then separated by LC, detected in multiple reaction monitoring (MRM) mass spectrometry mode via positive electrospray ionization. The analytes were quantified by matrix-matched standard solutions with external standard method. The limits of quantification (LOQs) of pyraclostrobin, thiophanate-methyl and carbendazim in different matrices were 5.8-7.0 μg/kg, 9.3-14.1 μg/kg and 2.1-2.6 μg/kg, respectively. For all the samples, the spiked recoveries ranged from 75.48% to 109.18%, and the relative standard deviations (RSDs) were 0.60%-5.11% (n=5). The method is quick, easy, effective, sensitive and accurate. The matrix-matched calibration solutions can efficiently compensate matrix effects of the pyraclostrobin, thiophanate-methyl and carbendazim in LC-MS/MS analysis. The established method can be applied to the residue analysis of the real samples of soil, citrus peel, citrus pulp and citrus fruits.

Use of Mixture Design with Minimal Restrictions to Optimize an Extraction Procedure Employing Diluted Acids Assisted by Ultrasound and Microwave for Nutrient Element Determination in Vegetal Samples

In this work, it was developed an alternative analytical strategy for the preparation of vegetal samples extracted with diluted acids and assisted by ultrasound and microwave radiation for the determination of nutrients elements by fast sequential flame atomic absorption spectrometer. The conditions optimized using univariate and multivariate methodologies for the procedure were as follows: 200 mg of sample; extraction solution comprising a mixture of 6.3 mL HNO3, 2.1 mL HCl, and 1.7 mL CH3COOH; extractor with a final concentration of 2.5 mol L-1; a sonication time of 30 min; and a microwave radiation time of 6 s. The accuracy of the procedure was confirmed by analyzing the certified reference material NIST 1515 (apple leaves) and by comparison with the results obtained through microwave-assisted total digestion method. The procedure was applied to determine Ca, Mg, Cu, Mn, Fe, and Zn in several cassava peel samples used in animal nutrition, and proved to be simple, reliable, fast, easy to implement, and inexpensive.

Presence of organochlorine pesticides in xoconostle (Opuntia joconostle) in the central region of Mexico

Mexico has many natural resources for use in the food industry. In recent years Xoconostle, which is considered as a traditional food, has gained importance due to key its components such as fiber, antioxidants, and fermentative bacteria found in both the peel and fruit, which could benefit human and animal health. Information on the presence of organic contaminants such as pesticides in Xoconostle is important in protecting its reputation as a healthy food. The objective of this research was to measure the concentration of pesticides in the peel of Xoconostle in four 50 m2 plots in the same production area. The samples were taken in the state of Hidalgo, which is one major region of production. Fruits were collected from upper and lower levels in five plots. Organochlorine pesticides in peel samples were extracted by Soxhlet extraction, purified with chromatographic columns, and finally analyzed by gas chromatography with electron capture detector (ECD). The results showed a predominance of heptachlor, HCH derivatives and DDT isomers but there is no permissible limit for these compounds in this fruit. The presence of organochlorines suggests the use of these compounds in control of pests in crops and livestock, in spite of the substitution of these compounds, principally by organophosphorus pesticides. Regulation is necessary to ensure the safety of the product for consumption and trade.

RAW264.7 대식세포에서 Citrus platymamma의 iNOS, COX-2, 염증성 사이토카인 발현 억제 효과

Citrus platymamma hort. ex Tanaka is widely used in traditional Korean medicine because of its medicinal benefits including an anti-inflammatory effect. This study aimed to evaluate changes in the flavonoid content and anti-inflammatory activities of C. platymamma during its harvest period. Fruit peel samples were obtained between September 2015 and February 2016. The results indicate that C. platymamma peel extract (CPE) was an effective inhibitor of lipopolysaccharide (LPS)-induced NO production in RAW264.7 cells. The inhibitory effects of CPE at 100 μg/mL concentration included dose-dependent decreases in the expression of iNOS and COX-2 proteins. In addition, CPE decreased the expression of pro-inflammatory cytokines TNF-α, IL-1β, and IL-6. The highest anti-inflammatory activity and flavonoid content were observed in CPE of C. platymamma peel harvested during the immature fruit period in September. Further, to assess the suitability of CPE for cosmetic use, we performed MTT assays using HaCaT keratinocytes and observed that CPE did not exhibit any cytotoxicity. To test the potential application of CPE as a cosmetic material, we also performed primary skin irritation tests on normal skin of 30 volunteers and no adverse reactions were observed. The results of this study indicate that CPE may be considered as an anti-inflammatory candidate for inclusion in cosmetic materials.

Selection of reliable reference genes for quantitative real-time PCR analysis in plum (Prunus salicina Lindl.) under different postharvest treatments

The reverse transcription quantitative real-time polymerase chain reaction (qRT-PCR) technique has become one of the most widely used and reliable methods in gene expression studies. Successful application of qRT-PCR requires the accurate quantification of relative transcript levels, which strongly depends on the expression stability of the reference genes used as internal controls for data normalization. Plums (Prunus salicina Lindl.) are among the most numerous and commercial important fruit trees. In order to ensure the reliability of gene expression analyses using qRT-PCR in plum molecular biology research, 14 candidate reference genes were selected, and their relative expression levels were further measured by qRT-PCR using samples of plum peels obtained via different postharvest processes. Three statistical algorithms, geNorm, NormFinder, and BestKeeper, were employed to assess the expression stability of each candidate gene. A comprehensive evaluation was generated by the overall analysis approach, RefFinder to infer the final rankings. The results showed that CAC was the most stably expressed candidate reference gene across all experimental conditions. CAC and UNK under the room temperature treatment, CAC, ACT, and CLATH under the cold treatment, and CAC and ACT under all treatments were suitable for accurate gene expression quantification. In addition, relative gene expression patterns of the plant anthocyanin biosynthesis-related structural gene PsANS were evaluated using selected housekeeping genes as internal controls under two treatments to further confirm the usefulness of the selected reference genes. These results indicated that the selection of systematically validated reference genes for specific experimental conditions is necessary to avoid misinterpretation of qRT-PCR data and to obtain accurate and reliable gene expression results.

Rheological properties of pomegranate peel suspensions: The effect of fibrous material and low-methoxyl pectin at acidic pH

The gel formation behaviour of four tunisian pomegranate peel powders was investigated at pH 3 in the presence of 30% sucrose and 1 g/L CaCl2. All gels show a rapid formation with G’>G″, which reveals a typically gel-like structure. Since the mechanical properties of pomegranate peel gels are governed mainly by soluble pectins and/or insoluble fibrous material, the rheological properties of pectin and fibrous material gels were individually investigated. Results show that all systems displayed a typical solid-like behaviour, however the profiles obtained for the fibrous material gels (35 g/L fibrous material) were quantitatively higher than those obtained for pectins (7 g/L pectin). Thus, the properties of the peel gels seem then to be mostly governed by fibrous material. However, the G′ and G″ moduli obtained for fibrous material and pectin gels were significantly lower than those of peel suspensions. The rheological properties of peel gels would thus result from a strong synergism between fibrous material and pectins. The mechanical treatment was found to have a significant effect on fibrous material gel strength improvement which could be related to a lower sedimentation of suspensions. The particle size distributions revealed a decrease of fibrous material's particle size, and so an increase in surface area and a decrease of suspension's sedimentation. By heating samples at 82 °C for 1 h, trimodal distributions were obtained for peel samples.

Enzyme-assisted extraction of proteins from Citrus fruits and prediction of their cultivar using protein profiles obtained by capillary gel electrophoresis

The suitability of protein profiles established by capillary gel electrophoresis (CGE) as a tool to discriminate between 11 cultivars of Citrus (orange and tangerine) peel and pulp was evaluated in this work. Before CGE analysis, different extraction buffers (which included enzyme-assisted treatments) were compared. The best results were achieved using 5% (v/v) Celluclast® 1.5 L and 5% (v/v) Palatase® 20,000 L buffers for Citrus peel and pulp protein extracts, respectively. The resulting protein profiles obtained were used to construct linear discriminant analysis (LDA) models able to distinguish Citrus peel and pulp samples according to their cultivar. In both cases, all samples were correctly classified with an excellent resolution among all categories, which demonstrated that protein patterns are a powerful tool to discriminate Citrus samples coming from different cultivars.

Rootstock selection, nitrogen and calcium influence postharvest disease in avocado

Field trials evaluating several parameters of growth, fruit yield and quality of 'Hass' avocado grafted to different rootstocks were established in 2004-2005 in four different growing regions of Australia. Fruit were harvested in three seasons from 2008, ripened and assessed for severity and incidence of anthracnose and stem end rot diseases. Peel samples were collected at harvest and analysed for concentrations of the cations (N, K, Ca, Mg). Rootstock significantly affected marketability of fruit (no stem end rot and less than 5% anthracnose) in 58% of the total number of trials evaluated, with better quality fruit harvested from 'Hass' grafted to Guatemalan or West Indian rootstocks such as 'A10' or 'Velvick'. Fruit quality was frequently poor from trees grafted to Mexican race rootstocks, regardless of growing location. Correlation analyses showed that fruit from rootstocks with superior fruit quality was often associated with lower skin N and higher Ca concentrations. There were significant positive correlations between anthracnose and skin N or N:Ca ratio in 75% of trials evaluated. There was a significant negative correlation between anthracnose and Ca in 42% of trials. The correlations between stem end rot and skin N (positive) or Ca (negative) were each significant in 42% of trials. Based on the results in this project, N:Ca ratios in the skin of unripe avocado fruit at harvest may provide one of the best indicators of potential postharvest disease in ripe fruit, and may have implications for fertiliser regimes.

Influence of the Peel on Predicting Soluble Solids Content of Navel Oranges Using Visible and Near-Infrared Spectroscopy

Abstract. The peel of orange was proven to influence light propagation within the fruit; thus, this study was aimed at investigating the influence of the peel on absorption spectra and calibration models within the wavelength range from 520 to 2200 nm. To investigate this effect further, the correlation between pulp soluble solids content (SSC) and peel SSC of the same oranges was studied. Spectra of 86 oranges with peel and peeled were collected using a commercial spectrometer, and partial least squares regression was used to develop calibration models. Results showed that for intact oranges, the calibration model using the visible and shortwave near-infrared (Vis-SWNIR) region (520-1100 nm) performed similarly to that using the Vis-NIR region (520-2200 nm), and the broader Vis-NIR region did not improve the calibration models. With respect to the influence of the peel, within the Vis-SWNIR and Vis-NIR regions, the models elaborated using peeled samples performed slightly better, but not significantly. In the NIR region, better results were obtained for models using intact samples. In addition, a linear correlation was found between pulp SSC and peel SSC, with a coefficient of determination (R 2 ) of 0.5047, which could be used to explain why the peel did not have significantly negative influence on prediction performance. It was concluded that the peel of navel orange did not have significant influence on the SSC determination using Vis/NIR spectroscopy, and the .

Growth Kinetics Parameters of Salmonella spp. in the Peel and in the Pulp of Custard Apple (Annona Squamosa)

The growth kinetic parameters (maximum growth rate, μ; lag time, λ and maximum population, k) of Salmonella spp. on the peel and in the pulp custard apple at 10, 15, 20 and 30°C were determinated. Samples of peel and pulp of custard apple were inoculated with a cocktail of three strains of Salmonella spp. (S. Typhimurium, S. Enteretidis and S. Montevideo) and further stored at 10, 15, 20 and 30°C. Salmonella can survive and multiply in both, the peel and in the pulp of the custard apple. Lower temperatures retard, but do not prevent Salmonella growth.

Phenolic and mineral profile of Balkan indigenous apple and pear cultivars

The aim of this study was chemical analysis of phenolic compounds, as well as mineral nutrients in pulp and peel obtained from Balkan indigenous apple and pear cultivars. Phenolic composition assesed by means of HPLC-DAD and spectrophotometric methods varied significantly between the cultivars for both peel and pulp. Among apples Mekica cultivar had the highest total phenolic content while Secerlija and Zlatna Parmenka had the lowest. In the case of pear samples the principal source of total phenolic content was Crna Takisa while their minimum was recorded for Bela Arapka. In most of the investigated samples chlorogenic acid in apples and arbutin in pears were major detected polyphenolic compounds. With regard to mineral analysis K was the most abundant followed by P, Mg, Ca and S. Iron was the dominant microelement in apple peel and pulp samples, while in pear samples the principal microelement was B. Obtained results provide detailed information on chemical composition of tested apple and pear cultivars and therby could encourage their wider cultivation and consumption.

Bioactive Flavonoids, Antioxidant Behaviour, and Cytoprotective Effects of Dried Grapefruit Peels (Citrus paradisi Macf.).

Grapefruit (Citrus paradisi Macf.) is an important cultivar of the Citrus genus which contains a number of nutrients beneficial to human health. The objective of the present study was to evaluate changes in bioactive flavonoids, antioxidant behaviour, and in vitro cytoprotective effect of processed white and pink peels after oven-drying (45°C–60°C) and freeze-drying treatments. Comparison with fresh grapefruit peels was also assessed. Significant increases in DPPH, FRAPS, and ABTS values were observed in dried grapefruit peel samples in comparison with fresh peels, indicating the suitability of the treatments for use as tools to greatly enhance the antioxidant potential of these natural byproducts. A total of thirteen flavonoids were quantified in grapefruit peel extracts by HPLC-MS/MS. It was found that naringin, followed by isonaringin, was the main flavonoid occurring in fresh, oven-dried, and freeze-dried grapefruit peels. In vivo assay revealed that fresh and oven-dried grapefruit peel extracts (45°C) exerted a strong cytoprotective effect on SH-SY5Y neuroblastoma cell lines at concentrations ranging within 0.1–0.25 mg/mL. Our data suggest that grapefruit (Citrus paradisi Macf.) peel has considerable potential as a source of natural bioactive flavonoids with outstanding antioxidant activity which can be used as agents in several therapeutic strategies.

Simultaneous determination of glucose, fructose, sucrose and sorbitol in the leaf and fruit peel of different apple cultivars by the HPLC–RI optimized method

A high performance liquid chromatography method with refractive index detection (HPLC–RI), for simultaneous determination of glucose, fructose, sucrose and sorbitol in leaf and/or apple peel samples from nine apple (Malus domestica Borkh.) cultivars and rootstocks, originating from a germplasm collection, has been developed and validated. Box–Behnken design of response surface methodology was applied for the method optimization. The Carbosep Coregel 87H3 column was used under the optimum conditions predicted: mobile phase of H2SO4 0.005molL−1 solution, flow rate of 0.3mLmin−1 and column temperature of 35°C. The method was validated for linearity (R2>0.99), limits of detection (2.67–4.83μgmL−1) and quantification (8.9–16.1μgmL−1), precision (%RSD<5.05) and recovery (93.94–103.06%) and satisfactory results obtained. The sugars content varied across micropropagated plants in vitro, plants regenerated after cryostorage, growing trees in vivo, and fruit peel.

BIOGAS PRODUCTION FROM CO-DIGESTION OF SELECTED AGRICULTURAL WASTES IN NIGERIA

The fear of depletion of fossil fuels and their attendant ecological effects and the high cost of renewable energy technology in Nigeria has triggered a need to develop alternative sources of energy, among which is biogas production. A slurry of 1 kg mixture of agro-waste feed stocks (plantain peel/rice husk, PP/RH; banana peel/plantain peel, BP/PP; and banana peel/rice husk, BP/RH) in 1:1 ratio was co-digested in locally fabricated digesters (10 L capacity). The experiment was run for 50 days and assessed for proximate content, biogas generation, organic matter, and mineral content in the digested and undi-gested agro-waste materials. The proximate composition showed that while banana peel had the highest moisture (56%), rice husk was highest in the content of ash (64%), crude protein (6.94%), and volatile solids (20%). The weekly cumulative biogas generation increased from 852.6 cm3 for BP/PP sample to 1049.7 cm3 for PP/RH sample for the 7 weeks at the experimental room temperature range of 29 oC to 35 oC. Sample PP/RH generated the highest volume of gas (biogas, methane, and others) compared to BP/RH and BP/PP samples. In each case the volume of gas production decreased in week 7 from 271.4 cm3 to 152.0 cm3 (for biogas), 161.4 cm3 to 97.1 cm3 (for methane), and 110.0 cm3 to 54.9 cm3 (for other gases). The nutritional concentrations of the digested and undigested mixture of the waste samples after Atomic Absorption Spectrophotometer (AAS) and Flame Photometry showed that the digested samples had higher contents of the nutritional elements than the undigested samples. The mineral elements ranged from 0.554 mg/g in the undigested rice husk to 18.155 mg/g in the digested banana peel samples. Fermentation of agricultural wastes to generate biogas and sludge with agricultural value offers an al-ternative and efficient method of agricultural wastes and energy management in Nigeria.

COMPARATIVE ANALYSIS OF COMPLEX MECHANICAL PROPERTIES OBTAINED IN TESTS ON FINISHED BOLTS AND TURNED SAMPLES

Purpose. The purpose of the work is provided by the system experimental study of the effect of strengthening the level of the ratio of complex mechanical properties of the finished bolts and peeled samples and analysis of the data on the basis of geometric and structural reinforcement. Methodology. A uniaxial tensile test was carried out on full-size bolts and the peeled samples to diameters of 10 mm and 8 mm at a testing machine FP - 100/1 recording full diagram of deformation and fracture. Findings. The level of strength of qualitatively and quantitatively has different effects on the characteristics of the ratio of resistance to plastic deformation and ductility characteristics ductile fracture resistance, determined on the finished bolts and peeled samples. At the same time, the analysis suggests that the combination of mechanical properties determined on finished bolts, the most adequate to their mechanical behavior during operation. This conclusion is particularly important for acceptance testing of bolts of strength class 8.8 or higher. Originality. For the first time experimentally shown that the system is functional cuts on specific metal products can have both hardening and softening effect on the characteristics of resistance to plastic deformation in terms of normal stress depending on the level of hardening and given an interpretation of the observed phenomena on the basis of changes in the ratio of the concentration of eg-tions and the degree of rigidity of the stress state in the cuts. Practical value. Limitation of mechanical tests are only willing bolts, other than greater consistency determines the properties of their structural strength bolts in the operation, reduce the overall time-consuming tests.

Proximate compositions, mineral contents and fatty acid compositions of native Amazonian fruits

The proximate compositions, mineral contents and fatty acid compositions of different parts (peel, pulp and seeds) of 10 native Amazonian fruits were chemically characterized. The peel and pulp showed high moisture contents (43.13 to 94.03%), while the seeds showed greater levels of ash values, total crude protein and total carbohydrates (0.55–3.35%, 1.55–15.34% and 17.78–65.64%, respectively). High levels of total lipids (from 14.40 to 34.70%) were found in piquiá (pulp and almond), in 2 varieties of umari (peel and pulp), uxi pulp and biribá seed. A wide range of mineral contents was detected (Mn: 0.32–11.96mg/100g; Zn: 0.39–4.75mg/100g; Cu: 0.52–16.21mg/100g; Fe: 0.91–9.88mg/100g; Mg: 30.02–219.44mg/100g; Na: 2.76–350.56mg/100g; P: 4.52–382.64mg/100g). The highest mineral levels were found in the samples of bacuri-azedo pulp (Mn, Zn), cubiu small seed (Cu), piquiá outer peel (Fe), cubiu large peel (Mg), all pajurá parts (Na) and piquiá almond (P). Fatty acid analysis identified and quantified 32 fatty acids. The highest levels of palmitic acid (16:0) and oleic acid (18:1n-9) were found in the peels and pulps of the 2 varieties of umari and uxi and in the pulp and almond of piquiá, while the highest levels of linoleic acid (18:2n-6) and α-linolenic acid (18:3n-3) were found in the seed of biribá and pulp of uxi, respectively. All samples of peels and pulps, except for piquiá pulp, had n-6/n-3 ratio less than 4. The samples showed good varied proximal composition and mineral levels, each being rich in at least one nutrient. Monounsaturated fatty acids and polyunsaturated fatty acids were found in higher concentrations in most samples. Peels and pulps presented good n-6/n-3 ratios and are considered beneficial to human health.

Pomelo (&lt;i&gt;Citrus maxima&lt;/i&gt;) Peel-Inspired Property for Development of Eco-Friendly Loose-Fill Foam

For development of eco-friendly packaging foam from pomelo peel, physical and mechanical properties of the pomelo peel and effects of pomelo varieties, namely Kao-Nampueng, Thong-Dee, and Kao-Pan, on their properties were investigated. It was found that the pomelo variety showed somewhat significant effect on physical and mechanical of pomelo peel properties. Because of its thick peel with high moisture content (75-80%) and water activity (0.90-0.98), the peel weight accounted for almost half of the total fruit weight. Cell structure and pore size of the peel were examined using the environmental scanning electron microscope (ESEM). The result showed an open cell foam structure with pore size of approximately 151±31 µm. The pore size was more open and large towards the outer surface. Uniaxial compression tests on pomelo peel samples with and without flavedo showed good reproducible stress-strain curves despite its biological variation. Young’s moduli of both samples were calculated to be 200-300 kPa and 110-210 kPa, respectively. Moreover, the most important property of packaging foam is the ability to absorb energy during impact which can be characterised through the measurement of the onset strain of densification. It was found that the strain values at the maximum energy absorption efficiency (εcd) of peel samples with and without flavedo for all studied pomelo varieties were comparable and were approximately in the range of 60-65%. These preliminary results indicate very promising mechanical properties of pomelo peel as eco-friendly packaging foam although further modifications are required to improve their physical and shelf-stability properties.

EXTENDING STORAGE LIFE OF COMMERCIALLY IMPORTANT TROPICAL FRUITS USING BIO-WAXES

Commercial storage of papaya and mango is restricted by postharvest diseases caused by fungi. The use of bio-waxes on storage life extension and quality retention of these commodities was investigated. Three different bio-waxes (chitosan, ITI wax 1 and ITI wax 2) formulated from locally available ingredients were used in this study. Papaya and mango harvested at commercial maturity were dipped in wax formulations and stored at low temperature at 13°C and 80% relative humidity for 7, 14 and 21 days. Since, chitosan is reported as an antifungal compound, an in vitro antifungal assay was also conducted for disease causing fungi, Colletotrichum spp. and Botryodiplodia spp. isolated from fruit prior to in vivo assay. In vitro studies on chitosan revealed significant inhibition on radial mycelial growth of the disease causing organisms isolated from these commodities at treatments of 1% chitosan and above. Significant changes were observed in all bio-wax coated fruits compared with non-treated controls with respect to peel colour, firmness, internal CO2 concentration and respiration rate while other organoleptic characteristics of fruit were not affected. Both papaya and mango coated with 1% chitosan and ITI wax 1 showed improved keeping quality with high marketability throughout the storage period of 14 days at 13±1°C plus 2 days at 28±2°C. Mangoes coated with the ITI wax 1 formulation showed storage life extension of 17 days at the same temperature. Significant increase in the activity of plant defense enzymes, chitinase and AŸ, 1-3, glucanase were observed in the papaya peel samples of chitosan coated fruits compared to controls. The results of this study confirmed that the storage life of these tropical fruits could be extended using bio-waxes without detrimental effects on external and internal quality of fruit.

Effect of pre-treatments on the saccharification of pineapple waste as a potential source for vinegar production

Properly saccharified pineapple waste can be considered the chief raw material for further fermentation into vinegar, which has wider applications as a food dressing or preservative both in industry and rural communities in developing countries. Previous investigations into the use of pineapple waste as a potential source for vinegar production highlighted the optimal conditions for the enzymatic hydrolysis step and outlined the need to facilitate enzyme access for saccharification. The effects of four physical pre-treatments were investigated to reduce biomass recalcitrance. Microwave heating (MW), boiling (B), cooking at high pressure with a pressure cooker (HPC) and with an autoclave (HPA) were carried out on peel and core samples for different lengths of time. When HPA preceded the enzymatic hydrolysis, the sugar yield was 70.2 g/kgfw and 72.8 g/kgfw from pineapple peel and core, respectively. When pineapple waste was subjected to HPC, B, or MW, the sugar yield obtained was lower than 60 g/kgfw. This study outlines the most effective pre-treatment method for obtaining a satisfactory sugar yield while maintaining practical feasibility when implementing the process prior to fermentation.