Speciation of essential nutrient trace elements in coconut water

An investigation on the effect of ultrasonication and microfiltration processing on the quality of king coconut (Cocos nucifera var. aurantiaca) water compared to minimal and thermal processing

The study aimed to investigate the effect of thermal and non-thermal processing on the physicochemical, microbial, and sensory characteristics of king coconut water. King coconut water samples were subjected to ultrasonication (50 kHz, 30 min at 35 °C), microfiltration (0.5 µm), and thermal treatments (at 90 °C for 10 min) with sodium metabisulfite (0.1 g/L) except the fresh sample (control). Samples were tested for physiochemical, microbial, and sensory parameters. Storage studies were conducted at 4 °C for 28 days. pH, titratable acidity, and total sugar of all treated samples were within the Sri Lankan Standard (SLS) limit (4.6-5.5, 0.07-0.1%, 4.1-6.5%, respectively) during the 28 days of storage. Sodium metabisulfite addition was significant in lowering the browning index. Antioxidant and phenolic contents of microfiltered and ultrasonicated samples varied between 49%-65% and 2.5-2.8 GAE mg/100 mL, respectively, during 4 weeks of storage, which was significantly higher compared to the heat-treated samples. Sensory evaluation scored the lowest attribute values for thermally treated samples. Microbial analyses indicated that microfiltered and ultrasonicated king coconut water remained safe for consumption for up to 4 weeks. Ultrasound and microfiltration, with the integration of sodium metabisulfite, were identified as effective methods for processing king coconut water while preserving its wholesome properties.

From ground to gut: Evaluating the human health risk of potentially toxic elements in soil, groundwater, and their uptake by Cocos nucifera in arsenic-contaminated environments

This study aimed to gauge the toxicity of potentially toxic elements (PTEs) in coconut crops cultivated in arsenic-contaminated areas while offering a global perspective encompassing more than 100 impacted countries. The current investigation provides crucial insights into the assessment of PTEs pollution using the Bioaccumulation factor, Geo-accumulation index, Potential ecological risk index, Hazardous index, and Lifetime cancer risk (LCR) and highlights the potential human health risks posed by contaminated food, water, and soil. From 22 severely polluted sites in West Bengal, India, soil, groundwater (GW), and coconut water (CW) samples were collected, acidified, and digested using microwave digestion, for PTEs quantification using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Results revealed that despite high concentrations of arsenic in soils (4.6 ± 3.4 mg kg-1), and GW (22.2 ± 150.9 μg L-1), CW (0.7 ± 3.1 μg L-1) levels were within permissible limits. Groups of PTEs with comparable sources and distributions were discovered through Principal Component Analysis (PCA). A speciation diagram was used to predict the prevalence of arsenic species in all three matrices. The Hazardous Index (HI < 1) indicated no probability of non-carcinogenic diseases for children and adults in all the compartments. However, exposure to GW and soil contaminated with Cr, As, and Cd by children (9.02 × 10-13 to 2.77 × 10-4) and adults (6.51 × 10-14 to 1.18 × 10-4) would increase their susceptibility to cancer (LCR >10-6). The study concluded that moderate lifetime consumption of CW is safe and has no significant impact on healthy individuals. Additionally, CW is a rich source of essential micronutrients such as Zn, Fe, Mn, and B. Overall, the findings of this study could help in developing appropriate strategies for reducing PTEs contamination and protecting human health.

Role of Thermal Process on the Physicochemical and Rheological Properties and Antioxidant Capacity of a New Functional Beverage Based on Coconut Water and Rice Flour

Different substrates have been implemented for the production of functional beverages. To avoid the presence of pathogens, beverages have been subjected to thermal treatments, such as sterilization or pasteurization, which can interfere with the physicochemical, rheological, functional, and organoleptic properties of the final product. The objective of the present study was to evaluate the effects of heat treatment on the physicochemical properties, such as acidity, pH, total solids, density, total and reducing sugar, as well as the antioxidant activity of a beverage formulated from rice flour (RF) and coconut water (CW). Three beverage formulations were evaluated: A (2% RF; 98% CW), B (5% RF; 95% CW), and C (8% RF; 92% CW), each of which was subjected to two heat treatments: sterilized (121 °C/15 psi/15 min) or pasteurized (60 °C/60 min and subsequently 73 °C/15 s). The heat treatments increased the acidity and reducing sugars but decreased pH, total sugar, and antioxidant activity. As for the rheological properties, the mixtures were pseudoplastic fluid. The physicochemical properties from RF and CW mixtures were dependent on the heat treatment, but these can be introduced as new nondairy substrates for the elaboration of functional beverages to be consumed mainly by those lactose intolerant.

Nicotianamine: A Key Player in Metal Homeostasis and Hyperaccumulation in Plants

Nicotianamine (NA) is a low-molecular-weight N-containing metal-binding ligand, whose accumulation in plant organs changes under metal deficiency or excess. Although NA biosynthesis can be induced in vivo by various metals, this non-proteinogenic amino acid is mainly involved in the detoxification and transport of iron, zinc, nickel, copper and manganese. This review summarizes the current knowledge on NA biosynthesis and its regulation, considers the mechanisms of NA secretion by plant roots, as well as the mechanisms of intracellular transport of NA and its complexes with metals, and its role in radial and long-distance metal transport. Its role in metal tolerance is also discussed. The NA contents in excluders, storing metals primarily in roots, and in hyperaccumulators, accumulating metals mainly in shoots, are compared. The available data suggest that NA plays an important role in maintaining metal homeostasis and hyperaccumulation mechanisms. The study of metal-binding compounds is of interdisciplinary significance, not only regarding their effects on metal toxicity in plants, but also in connection with the development of biofortification approaches to increase the metal contents, primarily of iron and zinc, in agricultural plants, since the deficiency of these elements in food crops seriously affects human health.

Fast-SEC coupled to ICP-MS for selected metal determination and its stability over time in polish wine

Metal ions contribute to the wine browning (as reaction catalysts), turbidity (in complexes), and astringency (due to interaction with tannins). Being aware that bioavailability and metabolism of metal ions in the human body are strictly related with their concentration and the form they occur it is important to monitor not only the total content of metals but also their speciation. Thus, we can obtain more information about their potential toxicity to human health. Present research shows the application of fast size exclusion chromatography (Fast-SEC) coupled to ICP-MS for the evaluation of the distribution of elements in different sized complexes in Polish wine. The study was focused on the selected ten elements (Al, B, Ba, Cu, Fe, Mn, Ni, Pb, Sr, Zn). Additional information of this work was the evaluation of the metal complex stability over time. Based on the obtained results, it can be seen that metal complexes present in the studied wine samples are stable even 10 months after the wine bottle opening.

Graphical abstract

Speciation of metals in indigenous plants growing in post-mining areas: Dihydroxynicotianamine identified as the most abundant Cu and Zn ligand in Hypericum laricifolium

Ag, As, Cu, Pb and Zn were found to be the principal metallic contaminants of a post-mining area of Peru (Hualgayoc, Cajamarca). Study of metal distribution amongst roots, stems, and leaves of four indigenous hypertolerant plant species, Arenaria digyna, Puya sp., Hypericum laricifolium, Nicotiana thyrsiflora indicated significant translocation of Zn (0.6 < TF ≤ 10.0) and Cu (0.4 < TF ≤ 6.5) into aerial plant organs and substantial water-extractable fraction (20-60%) of these metals, except for A. digyna (root and stems). A study of the metal speciation by ultrahigh-performance size-exclusion (fast-SEC) and hydrophilic ion interaction (HILIC) liquid chromatography with dual ICP (inductively coupled plasma) and electrospray (ESI) Orbitrap MS detection revealed the presence of nicotianamine and deoxymugineic acid copper and zinc complexes in roots, stem and leaves of N. thyrsiflora and Puya sp., and nicotianamine alone in A. digyna. A previously unreported compound, dihydroxy-nicotianamine was identified as the most abundant Cu and Zn ligand in H. laricifolium. The presence of arsenobetaine and an arsenosugar was confirmed by ESI MS. Ag and Pb were hardly translocated to leaves and were found as high molecular species; one of the Pb-containing species co-eluted in fast-SEC-ICP MS with rhamnogalacturonan-II-Pb complex commonly found in in the walls of plants.

A novel coconut-malt extract medium increases growth rate of morels in pure culture

Morels are gourmet wild edible mushrooms that can grow on several substrates with significant growth rate variations. Such variations have hindered the development of a standardized culture media to promote morel’s sustainable production. The aim of this study is developing a novel culture media that takes advantage of coconut water as a complementary component of culture media. Coconut water has been extensively used as a growth-promoting component for plant tissue cultures; however, its application as component of fungi cultivation medium has not been fully developed. This study confirms that coconut water can be efficiently used as culture media component for morels using a kinetic characterization. Morchella sp. kinetic growth is evaluated in different cultures: agar, malt extract agar (MEA), lactose, coconut water (15%) and combinations of them. Kinetic growth parameters (lag phase, λ and maximum specific growth rate, µ_max) are estimated using primary modeling methods. Among the selected models, the best fit is achieved using Baranyi’s model. A significant increase from 15.8% to 43.4% of the µ_max values was observed when culture media (agar, lactose, MEA) is supplemented with coconut water. The largest values of µ_max are obtained in MEA-coconut cultures (21.13 ± 0.43–22.57 ± 0.35). Micro-sclerotia and late sclerotia are observed in all cultures containing coconut water justifying the development of a feasible and cost-effective way of culturing morels. The results demonstrate that coconut water can be used for formulation of standard media for morel cultivation leading to a cheap alternative to produce dense mycelium and promote sclerotia formation.

Multivariate optimization of a dispersive liquid-liquid microextraction method for determination of copper and manganese in coconut water by FAAS

In this study, multivariate methodologies were applied in the optimization of a dispersive liquid-liquid microextraction (DLLME) method, aiming at the determination of Cu and Mn in coconut water samples by flame atomic absorption spectrometry. Some extractors (chloroform and CCl₄), dispersants (ethanol, methanol and acetonitrile) and complexing agents (5-Br-PADAP and Dithzone) were previously tested in the extraction. A mixture design was used to optimize the component proportions formed by chloroform (10%), acetonitrile (76%), and 0.020% 5-Br-PADAP solution (14%). Doehlert design optimized the variables pH, NaCl, and buffer amounts for the extraction of both metals. The following analytical characteristics, respectively for Cu and Mn, were accessed: limit of quantification (4.83 and 3.32 µg L^-1), enrichment factors (11 and 8 fold), and precision (6.6 and 6.0% RSD, n = 10). Addition/recovery tests of the analytes allowed to find values in the range of 96.5-120% for Cu and 99-107% for Mn.