Pineapple (Ananas comosus L.) By-Products Valorization: Novel Bio Ingredients for Functional Foods

Pineapple is consumed on a large scale around the world due to its appreciated sensorial characteristics. The industry of minimally processed pineapple produces enormous quantities of by-products (30–50%) which are generally undervalued. The end-of-life of pineapple by-products (PBP) can be replaced by reuse and renewal flows in an integrated process to promote economic growth by reducing consumption of natural resources and diminishing food waste. In our study, pineapple shell (PS) and pineapple core (PC), vacuum-packed separately, were subjected to moderate hydrostatic pressure (225 MPa, 8.5 min) (MHP) as abiotic stress to increase bromelain activity and antioxidant capacity. Pressurized and raw PBP were lyophilized to produce a stable powder. The dehydrated samples were characterized by the following methodologies: chemical and physical characterization, total phenolic compounds (TPC), antioxidant capacity, bromelain activity, microbiology, and mycotoxins. Results demonstrated that PBP are naturally rich in carbohydrates (66–88%), insoluble (16–28%) and soluble (2–4%) fiber, and minerals (4–5%). MHP was demonstrated to be beneficial in improving TPC (2–4%), antioxidant activity (2–6%), and bromelain activity (6–32%) without affecting the nutritional value. Furthermore, microbial and mycotoxical analysis demonstrated that powdered PC is a safe by-product. PS application is possible but requires previous decontamination to reduce the microbiological load.

Development and validation of a liquid chromatographic tandem mass spectrometric method for the analysis of patulin in apple and apple juice

This study reports a robust and sensitive method for rapid testing of patulin in apple and apple juice. The method involved extraction of homogenised samples (10 g) with ethyl acetate (10 mL) and clean up by dispersive-solid phase extraction using primary secondary amine (25 mg/mL). Prior to the LC-MS/MS analysis, the cleaned extract was reconstituted in methanol/water (2:8). The optimised LC-MS condition provided a symmetric peak of patulin within a short LC-runtime of 5 min. The recoveries at the limit of quantification (0.005 mg/kg) and higher levels were satisfactory (> 80%), with the precision-RSD_r (< 11%). In an inter-laboratory comparison study involving 13 accredited laboratories, the reproducibility-RSD_R and HorRat values ranged between 4.80 and 6.08% and between 0.18 and 0.23 respectively, indicating a satisfactory method-precision. The z-scores of the participating laboratories were within ± 2. When the method was applied to incurred samples, the contamination range was 0.008-0.225 mg/kg and 0.018-0.034 mg/kg for apple and juice respectively, demonstrating a satisfactory performance in terms of precision. Based on the solvent standard, matrix-matched standard and standard-addition approaches, the calibration graphs provided similar quantitative performances. Because of its reliability, robustness and time-effectiveness, the method can be recommended for regulatory testing purposes.

Risk assessment of patulin intake through apple-based food by infants and preschool children in Serbia

This study reports for the first time in Serbia the occurrence of patulin in apple-based food and the risk assessment associated with patulin intake by infants and preschool children. In total, 214 samples of infant fruit juices (48), infant purée (66), and juices for children (small package with straw, 100) were collected over 3 years (2013-15) and analysed using HPLC with ultraviolet detection. Patulin was found in 43.8% of infant juices and 16.7% of infant purée, with all values below the legal limit of 10 μg kg^-1 (maximum 8.3 and 7.7 μg kg^-1, respectively). The proportion of contaminated samples among fruit juices for children was 43.0%, with the highest patulin concentration at 30.2 μg kg^-1, not exceeding the maximum allowed level of 50 μg kg^-1. Risk assessment of patulin intake by Serbian infants and preschool children, conducted by deterministic and probabilistic approaches, revealed a hazard quotient well below 1, indicating a tolerable exposure level and no health concern.

Screening of a Combinatorial Library of Organic Polymers for the Solid-Phase Extraction of Patulin from Apple Juice

Patulin is a water-soluble mycotoxin produced by several species of fungi. Governmental bodies have placed it under scrutiny for its potential negative health effects, and maximum residue limits are fixed in specific food matrices to protect consumers’ health. Confirmatory analysis of patulin in complex food matrices can be a difficult task, and sample clean-up treatments are frequently necessary before instrumental analyses. With the aim of simplifying the clean-up step, we prepared a 256-member combinatorial polymeric library based on 16 functional monomers, four cross-linkers and four different porogenic solvents. The library was screened for the binding towards patulin in different media (acetonitrile and citrate buffer at pH 3.2), with the goal of identifying polymer formulations with good binding properties towards the target compound. As a proof of concept, a methacrylic acid-co-pentaerithrytole tetraacrylate polymer prepared in chloroform was successfully used as a solid-phase extraction material for the clean-up and extraction of patulin from apple juice. Clean chromatographic patterns and acceptable recoveries were obtained for juice spiked with patulin at concentration levels of 25 (64 ± 12%), 50 (83 ± 5.6%) and 100 μg L⁻¹ (76 ± 4.5%). The within-day and between-day reproducibility evaluated at a concentration level of 25 μg L⁻¹ were 5.6 and 7.6%, respectively.

Applicability of in vitro methods to study patulin bioaccessibility and its effects on intestinal membrane integrity

In human health risk assessment, ingestion of food is considered a major route of exposure to many contaminants, although the total amount of an ingested contaminant (external dose) does not always reflect the quantity available for the body (internal dose). In this study, two in vitro methods were applied to study bioaccessibility and intestinal membrane integrity of cells exposed to patulin, a mycotoxin with significant public health risk. Seven artificially contaminated fruit juices were assayed in the presence or absence of a standard meal, showing a significant difference for bioaccessibility values between contaminated samples alone (mean 27.65 ± 13.50%) and combinations with a standard meal (mean 7.89 ± 4.03%). Different concentrations of patulin (PAT) and cysteine (CYS) (protector agent) were assayed in Caco-2 cells monolayers. At 95 μM, PAT produced a marked decrease in transepithelial electrical resistance (TEER). This effect was significantly reduced when 400 μM and 4000 μM CYS was added to the cells. Combined use of in vitro digestion models with other techniques using intestinal cell lines, such as in vitro intestinal absorption models that use Caco-2 cells, may offer a more comprehensive model of what is occurring during digestion and absorption processes. The study of beneficial effects of protective agents would also be enhanced.

Quantitative analysis of patulin in apple juice by thin-layer chromatography using a charge coupled device detector

A method was developed and validated in-house for the detection and quantification of patulin in apple juice concentrate using a charge coupled device (CCD) on thin-layer chromatography (TLC) plates. Samples were extracted with ethyl acetate and then cleaned-up by extraction with a sodium carbonate solution. The method showed a mean recovery of 95%. The quantification and detection limit were 14 microg l(-1) and 0.005 microg per spot, respectively. The CCD camera is sufficiently sensitive to detect changes in spot fluorescence intensity caused by small differences in mycotoxin concentration under homogeneous illumination from a UV light source. The results of validation confirmed the efficiency of the method, which is sensitive enough to be used to quantify patulin in apple juice by producers or for government monitoring/survey programs. The method was applied to the analysis of 16 apple juice concentrate samples and patulin levels ranged from 15 to 46 microg l(-1). This study demonstrated the applicability of the TLC-CCD technique as a tool for monitoring patulin in apple juice.

Investigation of patulin contamination in apple juice sold in retail outlets in Italy and South Africa

A study of apple juice products sold in Italy and South Africa was initially carried out on 20 samples bought in Cesena, Italy, and Tygerberg in Cape Town, South Africa. The samples were bought at random and analysed for patulin contamination. All 12 of the Italian samples had no detectable levels of patulin, except one, which was just slightly above the lowest regulatory limit of 10 ng ml(-1). On the other hand, five of the eight South African samples were all contaminated with patulin levels above 10 ng ml(-1), with one showing a concentration of 75 ng ml(-1), well above the highest regulated limit of 50 ng ml(-1). This latter result led to a more targeted investigation with 14 samples being purchased in the low-income areas of Tygerberg where the initial samples were sourced. These samples confirmed that there might be a problem of mycotoxin contamination in apple juices products sold to low-income consumers because half of the samples showed patulin contamination of which four had levels well above the acceptable limits. This is the first study in South Africa to look at apple juice products in low-income areas and it points to a need to intervene and introduce quality systems in the supply chain of the manufacture and packaging of apple juice products by independent small business.

Inter-laboratory Study for Validation of a Japanese Official Analytical Method for Determination of Patulin in Apple Juice

To validate a modified version of AOAC official method of analysis 995.10 as an official standard in Japan for determination of patulin in apple juice, an inter-laboratory study was performed in 11 laboratories using a non-contaminated sample, 2 naturally contaminated samples and 2 spiked samples of apple juice. For naturally contaminated apple juices, the relative standard deviations for repeatability and reproducibility were 3.2, 7.1% and 10.0, 21.7%, respectively. HORRAT values were 0.4, 0.9. The average recovery of patulin from spiked sample was 83.7%. The limit of quantification was calculated as 10 microg/kg. From these results, the method was thought to be suitable as an official standard for determination of patulin in apple juice in Japan.