Pineapple Residues Research Articles

Potential of Endophytic Microorganisms in Fermentative Processes Using Agro-Industrial Waste as Substrates

This study investigated the potential of endophytic microorganisms in fermentative processes using agro-industrial residues as substrates. The aim was to explore sustainable biotechnological methods for producing valuable compounds from waste. Endophytic microorganisms were isolated from strawberry, lychee, and tangerine and used in fermentative processes with passion fruit, guava, and pineapple residues. Key methods included isolating and screening potent aroma-producing microorganisms, identifying them using MALDI-TOF MS, and analyzing volatile compounds by GC-MS. The results identified 37 endophytic microorganisms, with Kloeckera apiculata presenting the greatest aromatic potential. Fermentation with agro-industrial residues produced significant volatile compounds, identifying 27, 23, and 22 compounds from passion fruit, pineapple, and guava residues, respectively. The main conclusions highlighted the high production of ethyl acetate and 2-phenylethyl acetate, which contributed to fruity and floral aromas. The novelty of this study lies in the use of endophytic microorganisms isolated from tropical fruits to biotransform agro-industrial waste into high-value aromatic compounds, offering economic and environmental benefits. This research is significant, as it proposes a sustainable approach to valorize waste and produce natural aroma compounds through biotechnological processes.

Dynamics of co-composting of pineapple harvest and processing residues with poultry litter and compost quality

The production of pineapple generates significant quantities of harvest and processing residues, which are very little used. This study evaluates compost quality using pineapple residues and poultry litter. Five composting treatments were tested, varying following proportions of crown, pineapple processing wastes (PPW), pineapple harvest residue (PHR), and poultry litter (PL). Various parameters were analyzed, including pH, electrical conductivity, CO2 evolution rate, water content, organic carbon, nitrogen compounds, phosphorus, potassium, calcium, magnesium, copper, and zinc. Additionally, the perceptions of producers and processors regarding compost quality were gathered. Results indicated that microbial decomposition increased temperature, pH, CO2 release, and nitrogen content while reducing electrical conductivity and organic carbon. Composts demonstrated favorable characteristics for crop fertilization, with C4 (75% PHR + 25% PL) compost showing the best chemical properties. Producers and processors preferred the color, odor, and structure of C4 (75% PHR + 25% PL) and C5 (56.25% crown + 18.75% PPW + 25% PL) composts. Overall, composting pineapple residues with poultry litter yields composts suitable for plant fertilization, particularly C4 and C5 formulations, offering potential for sustainable waste valorization in agriculture.

Total mixed ration silages based on elephant grass with the addition of agro-industrial byproducts

The present study aimed to evaluate the fermentative profile and losses in total mixed ration silages based on elephant grass (Pennisetum purpureum Schum.) with the addition of agro-industrial byproducts. The experiment was conducted at Campus II, CCA/UFPB, Areia – PB, in a completely randomized design with six repetitions per treatment, totaling 30 experimental units. The agro-industrial byproducts used were pineapple residues, passion fruit peel, sisal mucilage, refinazil, corn bran, soybean meal, and cottonseed cake. Elephant grass constituted the basal forage of the diet. The treatments were as follows: T1: elephant grass + cottonseed cake + refinazil; T2: elephant grass + cottonseed cake + refinazil + pineapple residues; T3: elephant grass + cottonseed cake + refinazil + passion fruit peel; T4: elephant grass + cottonseed cake + refinazil + sisal mucilage; T5: elephant grass + corn bran + soybean meal. The silos remained closed for 68 days. The data were subjected to analysis of variance and Tukey's test, with a 5% significance level. The dry matter content of the silages varied from 32 to 44%. Regarding pH, treatments T2, T4, and T5 presented values above 4.5, while the others remained within the ideal range. No significant differences were observed between treatments regarding lactic acid bacteria (LAB) at the opening of the silages. The elephant grass silages including cottonseed cake and refinazil (T1 and T2) showed promise, with moderate losses and satisfactory presence of lactic acid bacteria. On the other hand, treatments that included passion fruit peel (T3) and sisal mucilage (T4) presented unfavorable conditions, with higher losses and significant presence of mold-forming microorganisms. Notably, the treatment with corn bran and soybean meal (T5) demonstrated adequate fermentation, with a significant increase in lactic acid bacteria, suggesting it to be a viable option for the production of elephant grass silage.

Biogas Production Potential of Mixed Banana and Pineapple Waste as Assessed by Long-Term Laboratory-Scale Anaerobic Digestion

Biogas is a renewable energy source generated through the anaerobic digestion (AD) of organic feedstocks. This study aims to quantify the biogas production potential (BPP) of fruit wastes via semi-continuous lab-scale mesophilic AD over a total of 100 days. The feed was composed of 80% banana peelings and 20% pineapple residues, mimicking the waste composition of a Costa Rican fruit processing facility used as a test case. The average loading rate of volatile suspended solids (VSS) corresponded to 3.6 kg VSS·m−3·d−1. Biogas yield and composition were monitored, along with the concentration of ammonium, volatile fatty acids, and pH. Discounting the start-up phase, the BPP averaged to 526 LN (kg VSS)−1 with a methane concentration of around 54%, suggesting suitability of the substrate for AD. We calculated that if upscaled to the Costa Rican test case facility, these values translate into a gross average heat and electricity production via AD of around 5100 MWhel·a−1 and 5100 MWhth·a−1, respectively. Deducting self-consumption of the AD treatment, this is equivalent to 73% of the facility’s electricity demand, and could save about 450,000 L of heavy oil per year for heat generation. To circumvent nitrogen shortage, the addition of a co-substrate such as dry manure seems advisable.

Assessing the Lead Removal Potential of Pineapple Waste Hydrochar in Simulated Wastewater Treatment

This study explores the viability of utilizing biochar and hydrochar derived from pineapple waste as adsorbents for removing lead (Pb) from water. Pineapple residues, including stems, leaves, and fruit, were subjected to pyrolysis and Hydrothermal Treatment to produce biochar (PWB) and hydrochar (PWH) respectively. Fourier Transform Infrared (FT-IR) analysis was employed to characterize the surface properties of PWB and PWH, validating their potential as adsorbents. A series of adsorption experiments assessed the impact of pH (ranging from 2 to 6), contact time (ranging from 15 to 90 minutes), and temperature (ranging from 30 to 90°C) on the adsorption efficiency of both materials. Results indicate PWH to be markedly more effective, with an average Pb removal efficiency of 84.07% compared to PWB's 55.68%. The optimal contact time was determined to be 60 minutes for both materials. Moreover, pH 4.0 was identified as the optimal condition for Pb adsorption, showcasing a significant increase in biosorption capacity within this pH range. Additionally, higher temperatures corresponded to enhanced Pb2+ removal efficiency, rising from 75.02% to 87.58% as temperature increased from 30°C to 90°C. Overall, these findings underscore the potential of pineapple waste-derived biochar and hydrochar as promising, environmentally friendly adsorbents for addressing heavy metal contamination in water, particularly in wastewater treatment applications.

Solid-State Fermented Pineapple Peel: A Novel Food Ingredient with Antioxidant and Anti-Inflammatory Properties.

It has been reported that pineapple (Ananas comosus) contains healthy nutrients and phytochemicals associated with antioxidant and anti-inflammatory capacities. However, a substantial amount of pineapple residue is produced due to a lack of valorization applications at the industrial scale, resulting in the loss of valuable nutrients. Solid-state fermentation (SSF) is proposed as an innovative strategy to enhance the release of bound phenolics from pineapple residues. In this work, the effects of SSF of pineapple peels with Lactobacillus plantarum, Lactobacillus rhamnosus, and Aspergillus oryzae on the release of phenolic compounds and their antioxidant and anti-inflammatory activities were evaluated, respectively. Pineapple peel extracts after SSF showed an increase in the release of phenolic compounds (248.11% with L. plantarum, 182% with A. oryzae, and 180.10% with L. rhamnosus), which led to an increase in the cellular antioxidant (81.94% with L. rhamnosus) and anti-inflammatory potential (nitric oxide inhibition of 62% with L. rhamnosus) compared to non-fermented extracts. Therefore, SSF of pineapple peels with L. plantarum, L. rhamnosus, and A. oryzae thrives as a new approach for the production of secondary metabolites with remarkable biological benefits, which can be the precursors for novel biofortified and nutraceutical-enriched foods that meet the needs of the most demanding and health-conscious consumers.

IMPORTANCE OF PINEAPPLE (Ananas comosus L.) WASTE AS A POSSIBLE SOURCE OF INDUSTRIAL PROTEASES

Pineapple (Ananas comosus L.) is a tropical fruit highly valued for its flavor, sweetness, aroma, and nutraceutical properties. The ‘Cayena Lisa’ cultivar is the most widely used for both fresh consumption and industrial purposes in Mexico. The municipalities of Tuxtepec and Loma Bonita, in the state of Oaxaca, produce around 582 thousand Mg of solid waste per year from fruit processing, to which the waste from plantations attacked by pests and diseases must be added. Consequently, these wastes must be processed in order to generate added value. Isolation of cysteine proteases from industrial residues is one possibility. In the present study, the parameters of the Mexican Official Standard for measuring pH (NOM-F-317-S-1978), total soluble solids (SST) (NMX-F-103-1982), and cysteine-protease activity in pineapple fruit processing residues at two stages of ripening over four months of harvest were used to determine whether there is a factor of quality attributes that correlates with the activity of this protein. In both ripening stages, cysteine-protease activity is higher in August. Regardless of the degree of ripening, peel and core are the best sources of cysteine-proteases. SST and pH values have no correlation with cysteine-protease activity, so they cannot be used as indicators of such activity. The findings show that ‘Cayena Lisa’ pineapple residues grown in Loma Bonita, Oaxaca, could be a good source of cysteine-proteases.

Dual Emerging Applications of Solid-State Fermentation (SSF) with Aspergillus niger and Ultrasonic-Assisted Extraction (UAE) for the Obtention of Antimicrobial Polyphenols from Pineapple Waste

The exploration of natural antimicrobial compounds is necessary due to the current bacterial resistance to synthetic antibiotics. For this reason, pineapple residues were evaluated as a natural source of phenolic compounds with antimicrobial capacity. Pineapple residues were fermented with A. niger GH1 and subjected to ultrasound for the extraction of phenolic compounds. In the solid-state fermentation (SSF), the peel and the core (70:30) were fermented for 32 h. Ultrasonic-assisted extraction (UAE) was optimized. The factors solid–liquid ratio (X1), ethanol concentration (X2), and extraction cycle (X3) were optimized through a Box–Behnken statistical design, using the total phenol content (TPC) as a response variable. The optimized and pre-purified extract with amberlite was characterized using HPLC-MS and we measured the antimicrobial activity against Listeria monocytogenes, Staphylococcus aureus, and Escherichia coli. The optimal values for X1, X2, and X3 were 82 mg/mL, 26%, and two cycles, respectively. The extract was effective as an antimicrobial agent against S. aureus and L. monocytogenes, with MICs of 50 mg/mL and 12.5 mg/mL, respectively; the bacterial growth curve and transmission electron microscopy (TEM) confirmed the antimicrobial activity. The main compounds identified in the antimicrobial extract were 3,4-DHPEA-EA, Phloretin 2′-O-xylosyl-glucoside, and Feruloyl tartaric acid. Overall, the combination SSF-UAE showed to be a promising strategy to recover phenolic compounds from pineapple residues, exhibiting great potential as a natural antimicrobial agent.

Extraction and Characterization of Bromelain from Pineapple Core: A Strategy for Pineapple Waste Valorization

Bromelain is a mixture of cysteine endopeptidase usually extracted from pineapple juice and is used for the treatment of various human diseases and in industrial applications. Bromelain demand is quickly increasing, and its recovery from pineapple residues appears to be a sustainable waste management strategy. Pineapple core is among the most significant waste materials in the production of canned pineapple and is richer in bromelain than other pineapple residues. In this project, we compared the enzymatic properties and composition of bromelain extracts from either pineapple core or pulp to address the recovery of bioactive bromelain from pineapple core, thus contributing to the valorization of this waste material. Although significant differences were detected in the protein content of the two preparations, no differences could be detected for their proteolytic activity and for the effect of pH on their enzymatic activity. Mass spectrometry (MS) approaches identified the same peptidases in the fruit and in the core. This confirmed the possibility of using pineapple core to obtain relevant amounts of bioactive bromelain by applying a relatively simple procedure, thus paving the way to implementing a circular economy in this specific industrial sector.

Lactiplantibacillus plantarum A1, C1 and C10 Are Potential Probiotics Isolated from Pineapple Residual Silage.

The production and consumption of pineapple creates large quantities of residues. Ensiling these residues might help to minimize the waste burden and meet the intensive feed demand for ruminants. Proper lactic acid bacteria (LAB) are not only responsible for pineapple residual silage fermentation, but might also deliver probiotics. The aim of this study was to isolate LAB strains with probiotic functions, and to enhance intestinal antioxidant capacity from naturally fermented pineapple residues. A total of 47 LAB isolates with gram-positive, catalase-negative, nonhemolytic properties were used for probiotic screening. Lactiplantibacillus plantarum (L. plantarum) A1, C1 and C10 were susceptible to rifampicin, gentamicin and erythromycin, did not contain virulence factor-coding genes and showed good tolerance to acid (pH 3.0), 0.5% bile salt and simulated gastric and intestinal fluid. Their hydrophobicity indices were 71.92%, 45.50% and 66.90%, respectively. All of them were able to adhere to bovine jejunum epithelial cells (BJECs) and to antagonize Escherichia coli F5 and Salmonella Dublin. These three LAB strains tolerated hydrogen peroxide and significantly decreased (p < 0.05) reactive oxygen species levels in BJECs. In addition, L. plantarum C1 and C10 significantly increased (p < 0.05) the total antioxidant capacity in BJECs in the presence of 200 μmol/L hydrogen peroxide condition. L. plantarum A1, C1 and C10 are potential probiotics isolated from pineapple residual silage. This study aims to promote pineapple residue's utilization in the feed industry.

Sustainable eutectic mixture-based ultrasound assisted multifaceted valorisation of pineapple waste for bromelain and bioethanol production

A large number of pineapple residues like peels, leaves and stems generated during processing remains underutilized. The current investigation provides one-pot task-specific valorisation of these residues by sequential extraction of bromelain and saccharification of cellulose residue for bioethanol production. Employing natural deep eutectic solvents (NADES) prepared by mixing ammonium salts with imidazole and glycerol has guaranteed sustainable extraction of bromelain. Ultrasound-assisted liquid phase microextraction (UA-LPME) was performed and NADES with moderate density (TBC:I:G/sodium sulphate) was observed to have a higher bromelain yield and purity. Response Surface Methodology-based optimization of UA-LPME was carried out and solid: liquid ratio (25 ml/g), ultrasound time (17.5 min) and ultrasound temperature (45 °C) were observed to be influential variables resulting in an optimal bromelain yield of (87%). Sequential fractionation of the enzyme concentrate with gel filtration chromatography and anion exchange chromatography has resulted in a corresponding purity fold of 89.27. The cellulose-rich residue remaining after bromelain extraction was enzymatically saccharified (Cellic CTec2) for bioethanol production (12.7 g/L). This novel approach guarantees sustainable valorisation of pineapple waste using NADES as a sustainable extraction medium.

Development, fermentation, and storage of kefir with extract of pineapple residues and Spirulina sp.

Fermented drinks of water kefir grains are a healthy option. The study aimed to evaluate the physical, chemical, sugar, active acid, and ethanol profiles, in the fermentation stages 0, 24, and 48 h, to obtain kefir fermented beverages from industrial pineapple and Spirulina residues. sp. biomass processing, after physicochemical characterization of these ingredients. Fermented drinks with the addition of pineapple extract and Spirulina sp. LEB 18 or with the addition of pineapple extract were characterized as acidic drinks. The study presented an average of 6.54°Brix and a higher content of sucrose and fructose when compared to the control drink. Only the fermented drink with Spirulina sp. LEB 18 remained stable in relation to the physicochemical parameters in storage at 4°C for 30 days. Water-based kefir beverages with the addition of pineapple residue extract and Spirulina sp. LEB 18 after future sensory analysis can be a healthy and viable option for consumption. Novelty impact statement The development of beverages with live microorganisms that seek the reuse of food peels is important since, in addition to providing a new product with bioactive potential, it also avoids waste.

High Sugar Production from Hydrolysate of Pineapple Residues via Integrated Enzyme‐Membrane System

The enzyme-membrane integrated system has become an attractive method for the depolymerization of lignocellulosic biomass. This research was planned to evaluate the effect of pH, temperature, enzyme loading, and reaction time in order to maximize the sugar production. Hydrolysate extracted from pineapple leaves was used as a substrate. The feed substrate was hydrolyzed by β-xylosidase under different working conditions using the one factor at a time (OFAT) method. The best working conditions, obtained via enzymatic hydrolysis were used in the enzyme-membrane integrated system. OFAT results revealed that the best working conditions were pH 7.5, 50 °C, 1% (w/v) and 30 mins. Sugar yield at simultaneous reaction and filtration was higher (293.94%) than the reaction alone (32.23%).

Valorization of Pineapple Residues from the Colombian Agroindustry to Produce Cellulose Nanofibers

Cellulose nanofiber is the world’s most advanced biomass material. Most importantly, it is biodegradable. In this work, nanofibers were obtained from pineapple leaves, a large solid waste in Colombia, using a combined extraction method (chemical procedures and ultrasound). The native fibers were bleached, hydrolyzed, treated with ultrasound, and characterized by scanning electron microscopy (SEM), infrared analysis (FTIR), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). As a comparison, a commercial microcrystalline cellulose sample was analyzed, which demonstrated the efficiency of cellulose extraction. The nanofibers had a diameter and a length of 18 nm and 237 nm, respectively, with a maximum degradation temperature of 306 °C. The analysis showed the efficiency of acid treatment combined with ultrasound to obtain nanofibers and confirmed that pineapple residues can be valorized by this method. These results indicate that lignocellulosic matrices from pineapple leaves have potential application for obtaining polymeric-type composite materials. Due to their morphology and characteristic physical properties, the cellulose nanofibers obtained in this work could be a promising material for use in a wealth of fields and applications such as filter material, high gas barrier packaging material, electronic devices, foods, medicine, construction, cosmetics, pharmacy, and health care, among others.

Avaliação do pré-tratamento com ultrassom como ferramenta para melhorar o processo de uma bebida fermentada a partir de subprodutos de abacaxi

Abstract Fermentation has the potential of converting fruit by-products into value-added products via an efficient, sustainable, and low-cost process. Traditionally, Mexicans use pineapple residues to produce a fermented beverage called tepache. As this soft drink is increasingly consumed in restaurants, it is necessary to develop an effective and reliable process to yield a final product with desirable physicochemical properties. In this work, tepache was prepared using an ultrasound pre-treatment to enhance the fermentation process and improve the end-product quality. The ultrasound was provided by a probe (25 kHz, 400 W) submerged in pineapple preparations before fermentation. Characterization of physicochemical properties was performed on samples processed under different types of amplitude (20 and 100%) and sonication time (5 and 10 min). In all samples, the pH, acidity, and ºBrix values were similar to those in commercial tepaches. On the other hand, microscopy revealed that 5 min of sonication induced positive changes in the suspended matter responsible for the physical stability of fruit beverages. The tepaches obtained with this method had color uniformity. Indeed, 5 min of sonication at the highest amplitude (16.34 kJ・cm-2) augmented the soluble solids during the initial phases of fermentation. Moreover, the results from IR spectroscopy proved that ultrasound helped the ethanol release from yeasts. The maximum ethanol yield, calculated by model fitting, had a positive variation of 35%. These findings prove that ultrasound is capable to induce physicochemical changes useful for the industrial production of tepache.

Development of fungal-mediated soil suppressiveness against Fusarium wilt disease via plant residue manipulation

BackgroundThe development of suppressive soils is a promising strategy to protect plants against soil-borne diseases in a sustainable and viable manner. The use of crop rotation and the incorporation of plant residues into the soil are known to alleviate the stress imposed by soil pathogens through dynamics changes in soil biological and physicochemical properties. However, relatively little is known about the extent to which specific soil amendments of plant residues trigger the development of plant-protective microbiomes. Here, we investigated how the incorporation of pineapple residues in soils highly infested with the banana Fusarium wilt disease alleviates the pathogen pressure via changes in soil microbiomes.ResultsThe addition of above- and below-ground pineapple residues in highly infested soils significantly reduced the number of pathogens in the soil, thus resulting in a lower disease incidence. The development of suppressive soils was mostly related to trackable changes in specific fungal taxa affiliated with Aspergillus fumigatus and Fusarium solani, both of which displayed inhibitory effects against the pathogen. These antagonistic effects were further validated using an in vitro assay in which the pathogen control was related to growth inhibition via directly secreted antimicrobial substances and indirect interspecific competition for nutrients. The disease suppressive potential of these fungal strains was later validated using microbial inoculation in a well-controlled pot experiment.ConclusionsThese results mechanistically demonstrated how the incorporation of specific plant residues into the soil induces trackable changes in the soil microbiome with direct implications for disease suppression. The incorporation of pineapple residues in the soil alleviated the pathogen pressure by increasing the relative abundance of antagonistic fungal taxa causing a negative effect on pathogen growth and disease incidence. Taken together, this study provides a successful example of how specific agricultural management strategies can be used to manipulate the soil microbiome towards the development of suppressive soils against economically important soil-borne diseases.CyJuYsbKET__Z9ZHp7dVcVVideo

Comparison of cellulose nanocrystals from pineapple residues and its preliminary application for Pickering emulsions

Pineapple, as a world-famous tropical fruit, is also prone to produce by-products rich in cellulose. In this study, different sections of pineapple, including pineapple core (PC), pineapple pulp (PPu), pineapple leaf (PL) and pineapple peel (PPe) were used for production of pineapple cellulose nanocrystals (PCNCs) by sulfuric acid hydrolysis. The crystallinity of PCNCs from PC, PPu, PL and PPe were 57.81%, 55.68%, 59.19% and 53.58%, respectively, and the thermal stability of PCNCs in order was PC > PL > PPe > PPu. The prepared PCNCs from PC, PPu, PL and PPe were needle like structure at the average aspect ratios of 14.2, 5.6, 5.5, and 14.8, respectively. Additionally, the differences in the structure and properties of PCNCs affected the stability of the prepared Pickering emulsions, which ranked as PPu > PPe > PL > PC. The Pickering emulsions stabilized by PCNCs prepared from PPu could be stored stably for more than 50 d. These results show the differences of PCNCs from four sections of pineapple, and provide isolated raw material selection for the further application of PCNCs.

Composting of Pineapple Residues and Food Waste: A Pilot-Scale Study

Spraying herbicide, followed by burning, is a common practice for clearing pineapple residues (leaves and stems) and preparing subsequent cultivation crops in the Mekong Delta, Vietnam. This is an unsustainable agricultural practice that causes environmental pollution. In this study, pilot-scale pineapple residue composting was studied at Tan Phuoc district, Tien Giang province. Approximately 5.5 t of pineapple leaves and stems were mixed with 10 wt% food waste and 0.1 % v/w effective microorganisms. Chopped pineapple residues and food waste were distributed in layers in sequence and sprayed with the microorganism solution. Composting was carried out in a pyramid-shaped pile with a bottom diameter of approximately 5 m and a height of about 1.5 m. The composting temperatures were monitored daily using a digital thermometer. The composting mixture was withdrawn, mixed thoroughly and then re-distributed to the composting pile every 3 d. Composting was performed after 45 d when the composting pile temperature almost reached ambient temperature. The compost product was subjected to pH and mesophilic/thermophilic microorganism cell density measurements. Phytotoxicity tests were carried out, and other important parameters such as organic content, useful/harmful microorganisms and heavy metals were determined. Mesophilic and thermophilic microorganism densities were approximately 2 x 108 and 3.8 x 107 CFU/g. The compost pH was 7.3, and the organic matter content reached 32.3 wt%. Heavy metals and harmful microorganisms, such as E. coli and Salmonella, were also within Vietnamese standards. Root length and number of roots were 372.8 % and 22.6 % higher than controls; stem length and diameter were 137.5 mm and 15.1 mm, and were not significantly different from controls (p

Pineapple Residue Ash Reduces Carbon Dioxide and Nitrous Oxide Emissions in Pineapple Cultivation on Tropical Peat Soils at Saratok, Malaysia

Burning pineapple residues on peat soils before pineapple replanting raises concerns on hazards of peat fires. A study was conducted to determine whether ash produced from pineapple residues could be used to minimize carbon dioxide (CO2) and nitrous oxide (N2O) emissions in cultivated tropical peatlands. The effects of pineapple residue ash fertilization on CO2 and N2O emissions from a peat soil grown with pineapple were determined using closed chamber method with the following treatments: (i) 25, 50, 70, and 100% of the suggested rate of pineapple residue ash + NPK fertilizer, (ii) NPK fertilizer, and (iii) peat soil only. Soils treated with pineapple residue ash (25%) decreased CO2 and N2O emissions relative to soils without ash due to adsorption of organic compounds, ammonium, and nitrate ions onto the charged surface of ash through hydrogen bonding. The ability of the ash to maintain higher soil pH during pineapple growth primarily contributed to low CO2 and N2O emissions. Co-application of pineapple residue ash and compound NPK fertilizer also improves soil ammonium and nitrate availability, and fruit quality of pineapples. Compound NPK fertilizers can be amended with pineapple residue ash to minimize CO2 and N2O emissions without reducing peat soil and pineapple productivity.

Pineapple (<i>Ananas comosus</i> L. Merr.), Waste Streams, Characterisation and Valorisation: An Overview

Processing pineapple industry produces huge amounts of waste thus contributing to worsen the global environmental problem. Valorising pineapple waste through further processing until it is transformed into valuable products using environmentally friendly techniques is both, a challenge, and an opportunity. The aim of this review is to characterize and highlight the phytochemical constituents of pineapple peel, their biological activity, and to evaluate the current state-of-art for the utilization of pineapple waste from the processing industry for obtaining pharmaceuticals, food, and beverages, biocombustibles, biodegradable fibers, and other different usage. Pineapple residues are rich in many bioactive compounds such as ferulic acid, vitamin A and C as antioxidant, and containing alkaloids, flavonoids, saponins, tannins, cardiac glycoside, steroids, triterpenoids and phytosterols may provide a good source of several beneficial properties, as well as bromelain that showed significant anticancer activity. Also, pineapple processing residues contain important volatile compounds used as aroma enhancing products and have high potential to produce value-added natural essences. Pineapple peels can be used as nonpharmacological therapeutical in the form of processed food and instant drinks; its potent natural antimicrobial properties may be applied for food conservation and as potential leads to discover new drugs to control some infectious microbial. Pineapple waste is a promising source of metabolites for therapeutics, functional foods, and cosmeceutical applications.