Water content quantification of raw polysaccharide materials for food processing is generally performed by gravimetric analysis or titrimetric methods, which are time- and energy-consuming, non-eco-friendly and sample destructive. The present study develops and validates a new approach, based on the use of Fourier transform infrared (FTIR) spectroscopy, resulting in a model of the water content of carboxymethyl cellulose (CMC) polysaccharides. Samples of CMC were exposed to different relative humidity conditions. Water content was determined by standard gravimetric methods (OIV-Oeno 404–2010) and compared with the area of FTIR absorption in the range 3675–2980 cm⁻¹, attributed to the stretching of OH groups. The strong correlation between gravimetric results and FTIR area (R² = 0.88) showed no signs of bias across the water content range. A cross-validation technique to predict the water content by band area was assessed obtaining a general equation: y = 2.12 x + 2.80 with a high repetitively and good prediction of the tested models.

Chlorine is a widely used disinfectant and oxidant used for an array of municipal and industrial applications, including potable water, swimming pools, and cleaning of membranes. The most popular method to verify the concentration of free chlorine is the colorimetric method based on DPD (N, N-diethyl-p-phenylenediamine), which is fast and reasonably cheap, but DPD and its product are potentially toxic. Therefore, a novel, environmentally friendly colorimetric method for the quantification of residual chlorine based on the food additive pyridoxamine (4-(aminomethyl)-5-(hydroxymethyl)-2-methylpyridin-3-ol) was investigated. Pyridoxamine is a B6 vitamin with an absorption maximum at 324 nm and fluorescence emission at 396 nm. Pyridoxamine reacts rapidly and selectively with free chlorine, resulting in a linear decrease both in absorbance and in emission, giving therefore calibration curves with a negative slope. The pyridoxamine method was successfully applied for the quantification of free chlorine from 0.2 to 250 mg/L. Using 1 cm cuvettes, the limit of quantification was 0.12 mg Cl₂/L. The pyridoxamine and the DPD methods were applied to actual environmental samples, and the deviation between results was between 4% and 9%. While pyridoxamine does not react with chloramine, quantification of monochloramine was possible when iodide was added, but the reaction is unfavourably slow.

Continued rise in global human population, per capita consumption, urbanization and migration towards coastal cities present challenges in fulfilling the energy, water and food demands of coastal communities in sustainable manner. In this regard, as a solution to the problem, a new multigeneration system is proposed to address some of the most common and vital needs of such communities. The system developed is based on principles of sustainability and decentralisation and is driven by renewable energy sources including sun and biomass. It provides electricity, fresh water, hot water for domestic use, HVAC for space air-conditioning and food storage, in addition to hot air for food drying. In the proposed hybrid system, biomass energy is integrated with solar energy in a complimentary manner as a means to maximise outputs and enhance system resilience against weather conditions and day/night cycles. Designing for resilience enables a type of operation that fulfils parallel demands in a continuous stable and flexible operation which can be optimised depending on the requirements. The main sub-systems used in the proposed multigeneration system consist of a Biomass combustor, Concentrated Solar Power (CSP), a Rankine Cycle, a desalination unit and an Absorption Cooling System (ACS). A comprehensive integrated thermodynamic model of the entire system is developed by application of energy, mass, entropy and exergy balance equations. Moreover, effects of various inputs and environmental variables on the outputs and performance has also been studied. Results reveal that the proposed system is capable of fulfilling some of the coastal community’s essential requirements in an efficient and ecologically benign manner. The energy and exergy efficiencies of the proposed system are 55% and 18%, respectively. The outputs of the system include 1687 m³/day of produced fresh water, ~4 MW of cooling, ~13 MW of electricity, ~73 kg/s of hot air for food drying, and ~41 kg/s of hot water for domestic use. Furthermore, the highest amount of exergy destruction is observed in biomass combustion unit and the solar PTCs.

A novel method of hydrofluidisation food freezing is numerically investigated in this paper. This technique is based on freezing small food products in a liquid medium under highly turbulent flow conditions when the heat transfer coefficient is higher than 1 000 W⋅m⁻²⋅K⁻¹, which depends on the operating and flow conditions. A numerical model was developed to characterise the freezing process in terms of the heat transfer and diffusion of liquid solution components into the food product. The study investigates the freezing process of spherical samples in binary solutions of ethanol (30%) and glycerol (40%) and ternary solution of ethanol and glucose (15%/25%). The developed model was employed to determine the concentration of the liquid solution in food samples and to quantify the effect of sample size, heat transfer coefficient, solution temperature and concentration on the process. The food sample size varied from 5 to 30 mm, and the heat transfer coefficients varied from 1 000 to 4 000 W⋅ m⁻²⋅ K⁻¹. The results confirm that a freezing time of 15 min for 30 mm diameter samples or less than 1 min for 5 mm diameter samples can be achieved with the hydrofluidisation method. The solution uptake was influenced by the solution type, sample size and process parameters and varied from 8.9 to 35 g of solute per kg of product for ethanol-glucose and glycerol solutions, respectively. This paper quantifies the advantages and possible limitations of hydrofluidisation, which has not yet been entirely studied, especially in terms of the mass absorption of different solutes.

In recent years, the incidence of dental erosion caused by the ingestion of acidic foods and drinks, including sports drinks, has been increasing in Japan and elsewhere. Therefore, the problems associated with this injury can no longer be ignored in dental clinical practice. The ingestion of these foods and drinks is important from the viewpoint of overall health and disease prevention. For example, fermented foods, such as Japanese pickles, enhance the nutritional value of foodstuffs and promote the absorption of nutrients into the body, and sports drinks are useful for preventing heat stroke and dehydration. Therefore, eliminating these intakes is not a viable solution. In this paper, we outline the mechanism of dental erosion caused by acidic beverages and also describe the effectiveness of alkaline ionized water (AIW) at preventing acid erosion. Given the fact that the complete elimination of acidic beverage consumption is highly unlikely, remedies such as the use of alkaline ionized water (AIW) may be helpful.

A dispersive liquid–liquid microextraction procedure for lead(II) as its 5-(4-dimethylaminobenzylidene) rhodanine complex has been established prior to its microsampling flame atomic absorption spectrometric determination. The influences of various analytical parameters including pH, solvent type and volume, dispersive solvent type and volume, 5-(4-dimethylaminobenzylidene) rhodanine amount, salt effect, and centrifugation time and speed were investigated. The effects of certain alkali, alkaline earth, and transition metal ions on the quantitative extraction of lead(II) were also studied. Quantitative recoveries were obtained at pH 6. The enrichment factor was calculated as 125. The detection limit for lead is 1.1 μg/L. The accuracy of the method was tested with the additions recovery test and analysis of the standard reference materials (SPS-WW2 waste water, NIST SRM 1515 apple leaves, and TMDA-51.3 fortified water). Applications of the present procedure were tested by analyzing water and food samples.

Compatibility of CNF with three polysaccharides having different surface charges and backbones (chitosan, methyl cellulose, and carboxymethyl cellulose) was investigated. Chitosan (CH) incorporation reduced water absorption (WA) of CNF films (P < 0.05). CH molecular weight (Mw) (68, 181, 287 kDa) and amount (10 and 20 g/100 g CNF in dry basis) impacted moisture barrier, mechanical, antibacterial, thermal, and structural properties of CNF films. Regardless of Mw, CH incorporation (20 g/100 g CNF) decreased (P < 0.05) WA of CNF films, and high Mw (287 kDa) CH (20 g/100 g CNF) incorporation resulted in lower film water solubility while increasing film water vapor permeability compared with low Mw CH (68 kDa) incorporation (P < 0.05). CNF film with low Mw CH (20 g/100 g CNF) exhibited antibacterial activity against L. innocua and E. coli. Interaction mechanisms between CH and CNF were investigated through thermal, structural, and morphology analyses using DSC, FTIR, and SEM, respectively. CNF films with low or high Mw CH incorporation (20 g/100 g CNF) were further validated as surface contact films for fresh beef patties, showing effectiveness to prevent moisture transfer between the layered patties. This study demonstrated the potential of using CNF-CH composite films as water resistant and antibacterial packaging for foods with high moisture surfaces.

In this study, ultralayered Co₃O₄ adsorbent was synthesized and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The surface area of the solid material was found to be 75.5m²g⁻¹ by BET method. The ultralayered Co₃O₄ was used for the first time as an effective adsorbent for the preconcentration of the Pb(II) ions in various samples prior to flame atomic absorption detection. Analytical parameters affecting the solid phase extraction of Pb(II) such as pH, adsorption and elution contact time, eluent volume and concentration, sample volume and common matrix ions were investigated. The recovery values for Pb(II) were found to be ≥92% even in the presence of 75,000mgL⁻¹ Na(I), 75,000mgL⁻¹ K(I), and 75,000mgL⁻¹ Ca(II) ions. 10s vortexing time was enough for both adsorption and elution contact times. The elution was easily made with 2mL of 2.0molL⁻¹ HNO₃. The reusability (170 cycles) and adsorption capacity (35.5mgg⁻¹) of ultralayered Co₃O₄ were excellent. The preconcentration factor of the method and detection limit were found to be 175 and 0.72µgL⁻¹, respectively. The described method was validated with certified reference material (RM 8704 Buffalo River Sediment, BCR-482 Licken and SPS-WW1 Batch 111-Wastewater) and spiked real samples. It was also applied for the preconcentration of Pb(II) ions in various water (well water, mineral water, waste water and sea water), food (cauliflower and barley), street sediment and tobacco samples.

A simple, rapid, sensitive and environmentally friendly separation and preconcentration procedure, based on the carrier element free coprecipitation (CEFC) of Cu(II) and Cd(II) ions by using an organic coprecipitant, 2-{[4-(4-fluorophenyl)-5-sulphanyl-4H-1,2,4-triazol-3-yl]methyl}-4-{[(4-fluorophenyl) methylene]amino}-5-(4-methylphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-one (MEFMAT) was developed. The analyte ions were determined by flame atomic absorption spectrometric (FAAS) determinations. The optimum conditions for the coprecipitation process were investigated on several commonly tested experimental parameters such as pH of the solution, amount of MEFMAT, sample volume, standing time, centrifugation rate and time. The influences of some anions, cations and transition metals on the recoveries of analyte ions were also investigated, and no considerable interference was observed. The preconcentration factor was found to be 50. The detection limits for Cu(II) and Cd(II) ions based on the three times the standard deviation of the blanks (N:10) were found to be 1.49 and 0.45μgL⁻¹, respectively. The relative standard deviations were found to be lower than 3.5% for both analyte ions. The method was validated by analyzing two certified reference materials (CRM-TMDW-500 Drinking Water and CRM-SA-C Sandy Soil C) and spike tests. The procedure was successfully applied to sea water and stream water as liquid samples and tobacco, hazelnut and black tea as solid samples.