Osmotic dehydration of apples in sugar/salt solutions: Concentration profiles and effective diffusion coefficients

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Diffusion coefficients during osmotic dehydration of tomatoes in ternary solutions

The apparent diffusion coefficients for sucrose, NaCl and water during osmotic dehydration of tomatoes in ternary solutions were determined. Long time experiments (up to 60 h) were carried out in order to determine equilibrium concentrations inside tomatoes, whereas short time experiments (up to 4 h) were performed to provide detailed information on kinetics of water loss and solids gain at the beginning of osmotic treatment. The mass transfer rates for water and solutes showed to be dependent of NaCl and sucrose concentrations in osmotic solution and simple regression models as functions of solutes concentration were determined for diffusion coefficients. Salt and sucrose diffusivities showed to be interdependent, with increasing NaCl concentration causing the enhancement of water loss, at the same time that higher sucrose contents hindered the excessive salt penetration. (C) 2003 Elsevier Ltd. All rights reserved.

Temperature and concentration dependence of heat capacity of model aqueous solutions

Heat capacities of binary aqueous solutions of different concentrations of sucrose, glucose, fructose, citric acid, malic acid, and inorganic salts were measured with a differential scanning calorimeter in the temperature range from 5degreesC to 65degreesC. Heat capacity increased with increasing water content and increasing temperature. At low concentrations, heat capacity approached that of pure water, with a less pronounced effect of temperature, and similar abnormal behavior of pure water with a minimum around 30degreesC-40degreesC. Literature data, when available agreed relatively well with experimental values. A correction factor, based on the assumption of chemical equilibrium between liquid and gas phase in the Differential Scanning Calorimeter, was proposed to correct for the water evaporation due to temperature rise. Experimental data were fitted to predictive models. Excess molar heat capacity was calculated using the Redlich-Kister equation to represent the deviation from the additive ideal model.

Effect of heated solutions on decay control and residues of imazalil in lemons

Freshly harvested lemons [(Citrus limon (L.) Burm)] were dipped 3 min in water with and without imazalil (IMZ) at 50, 100, and 200 ppm at 50 degrees C and at 1000 ppm IMZ at 20 degrees C. Following treatments fruit were kept at 9 degrees C and 90%-95% relative humidity (RH) for 13 weeks and an additional week at 21 degrees C and ca. 75% RH, to simulate a marketing period (SMP). No decay control was observed with fruit dipped in water at 50 degrees C. In contrast, IMZ treatments provided 90%-96% control of Penicillium rots during cold storage and SMP. Fungi other than Penicillium spp. were also found in all samples as differences among treatments were negligible. IMZ treatment caused some external damage to the fruit (peel browning), and the percentage of damaged fruit was related to the amount of active ingredient (AI) present in it. Dipping in 200 or 1000 ppm IMZ promoted off-flavor development after 10 weeks of storage, and fruit were judged to be unacceptable for consumption after 13 weeks of cold storage. After 1000 ppm IMZ dipping at 20 degrees C, residue concentration in fruit was 8.20 ppm; this value doubled that found in a previous investigation on lemons treated with comparable IMZ levels. Residue concentrations in fruit after treatment at 50 degrees C was strictly related to the amount of fungicide employed. After 13 weeks Al residues in fruit decreased to average ca. 35% of the initial values. During the 1 week SMP, residue levels decreased by a further ca. 25%. It was concluded that it is possible to achieve significant control of decay in lemons during longterm storage by dipping fruit in 50 ppm IMZ mixtures at 50 degrees C. Such treatment should be advised to remarkably reduce potential pollution in the environment due to packinghouse wastewater disposal.

Viscosity of aqueous carbohydrate solutions at different temperatures and concentrations

Experimental viscosity values of sucrose, glucose, and fructose aqueous solutions in a large range of temperatures (0 to 85 degrees C) and concentrations (10 to 60% w/w) that might be encountered in food processes were obtained in order to contribute to extending the available database of food properties. The temperature dependence of viscosity could be adequately described by the Arrhenius model, and the activation energy was well represented by a unique function of the solute volume fraction, valid for sucrose, glucose, and fructose solutions.

Behavior of plant tissue in osmotic solutions

The effect of the concentration of sucrose solutions on the cellular structure of potato tissue in equilibrium at 27 degreesC was Studied. Two different methods of investigation were used to determine the volume of the different phases composing the cellular tissue of the potato when in equilibrium with the solutions. one based on data of the concentration itself and the overall volume of 2 mm slices after 48 h at equilibrium, and the other on microscopic images of cells in thin slices of fresh tissue stained with neutral red after an hour in equilibrium to show protoplasts, vacuoles and plasmolysis spaces. The results of these methods were compared with those obtained by a predictive thermodynamic approach considering the semipermeability of cell membranes. Phase volume data obtained from microscopic analysis were more similar to what was predicted by the theoretical model than those obtained by means of composition measurement. where the long equilibrium time apparently led to the loss of semi permeability of the cell membranes, since total volumes calculated without consideration of the cell membranes were similar to those measured. This suggests that the length of time of osmotic dehydration brings about a change in cell structure and the consequent involvement of a different mechanism in mass transfer. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Mineral loss and color change of enamel after bleaching and staining solutions combination

Pigments of food and beverages could affect dental bleaching efficacy. The aim of this investigation was to evaluate color change and mineral loss of tooth enamel as well as the influence of staining solutions normally used by adolescent patients undergoing home bleaching. Initial hardness and baseline color were measured on enamel blocks. Specimens were divided into five groups (n = 5): G1 (control) specimens were kept in artificial saliva throughout the experiment (3 weeks); G2 enamel was exposed to 10% carbamide peroxide for 6 h daily, and after this period, the teeth were cleaned and stored in artificial saliva until the next bleaching session; and G3, G4, and G5 received the same treatments as G2, but after bleaching, they were stored for 1 h in cola soft drink, melted chocolate, or red wine, respectively. Mineral loss was obtained by the percentage of hardness reduction, and color change was determined by the difference between the data obtained before and after treatments. Data were subjected to analysis of variance and Fisher's test (a = 0.05). G3 and G5 showed higher mineral loss (92.96 +/- 5.50 and 94.46 +/- 1.00, respectively) compared to the other groups (p = 0.05). G5 showed high-color change (9.34 +/- 2.90), whereas G1 presented lower color change (2.22 +/- 0.44) (p = 0.05). Acidic drinks cause mineral loss of the enamel, which could modify the surface and reduce staining resistance after bleaching. (C) 2013 Society of Photo-Optical Instrumentation Engineers (SPIE)

Assessment of the breakdown products of solar/UV induced photolytic degradation of food dye tartrazine

The food dye tartrazine (CI 19140) was exposed to UV irradiation from an artificial source, a mercury vapor lamp, and a natural one, sunlight. It was observed that conditions such as energy dose, irradiation time, pH and initial dye concentration affected its discoloration. There was 100% of color removal, after 30 min of irradiation, when a dye solution 1 x 10(-5) mol L-1 was submitted to an energy dose of 37.8 J cm(-2). Liquid Chromatography coupled to Diode Array Detection and Mass Spectrometry confirmed the cleavage of the chromophore group and the formation of five by-products at low concentration. Although by-products were formed, the Salmonella/microsome mutagenicity assay performed for both, the dye solution at a dose of 5.34 mg/plate and the solutions obtained after exposure to UV irradiation, did not present mutagenic activity for TA98 and TA100 with and without S9. (C) 2014 Elsevier Ltd. All rights reserved.

Physicothermal properties of aqueous sodium chloride solutions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

In situ Evaluation of the Erosive Potential of Orange Juice Modified by Food Additives

The aim of this study was to evaluate the erosive potential of orange juice modified with food-approved additives: 0.4 g/l of calcium (Ca) from calcium lactate pentahydrate, 0.2 g/l of linear sodium polyphosphate (LPP) or their combination (Ca+LPP) were added to a commercially available orange juice (negative control, C-). A commercially available calcium-modified orange juice (1.6 g/l of calcium) was the positive control (C+). These juices were tested using a short-term erosion in situ model, consisting of a five-phase, single-blind crossover clinical trial involving 10 subjects. In each phase, subjects inserted custom-made palatal appliances containing 8 bovine enamel specimens in the mouth and performed erosive challenges for a total of 0 (control), 10, 20, and 30 min. Two specimens were randomly removed from the appliances after each challenge period. Enamel surface microhardness was measured before and after the clinical phase and the percentage of surface microhardness change (%SMC) was determined. Before the procedures, in each phase, the subjects performed a taste test, where the juice assigned to that phase was blindly compared to C-. Overall, C+ showed the lowest %SMC, being the least erosive solution (p < 0.05), followed by Ca+LPP and Ca, which did not differ from each other (p > 0.05). LPP and C- were the most erosive solutions (p <0.05). Taste differences were higher for C+ (5/10 subjects) and Ca (4/10 subjects), but detectable in all groups, including C- (2/10 subjects). Calcium reduced the erosive potential of the orange juice, while no protection was observed for LPP. Copyright (C) 2012 S. Karger AG, Basel

Agrofood chain analysis: production, commercialisation and consumption of healthy food for population at risk of poverty in Italy

Italy registers a fast increase of low income population. Academics and policy makers consider income inequalities as a key determinant for low or inadequate healthy food consumption. Thus the objective is to understand how to overcome the agrofood chain barriers towards healthy food production, commercialisation and consumption for population at risk of poverty (ROP) in Italy. The study adopts a market oriented food chain approach, focusing the research ambit on ROP consumers, processing industries and retailers. The empirical investigation adopts a qualitative methodology with an explorative approach. The actors are investigated through 4 focus groups for consumers and carrying out 27 face to face semi-structured interviews for industries and retailers’ representatives. The results achieved provide the perceptions of each actor integrated into an overall chain approach. The analysis shows that all agrofood actors lack of an adequate level of knowledge towards healthy food definition. Food industries and retailers also show poor awareness about ROP consumers’ segment. In addition they perceive that the high costs for producing healthy food conflict with the low economic performances expected from ROP consumers’ segment. These aspects induce a scarce interest in investing on commercialisation strategies for healthy food for ROP consumers. Further ROP consumers show other notable barriers to adopt healthy diets caused, among others, by a personal strong negative attitude and lack of motivation. The personal barriers are also negatively influenced by several external socio-economic factors. The solutions to overcome the barriers shall rely on the improvement of the agrofood chain internal relations to identify successful strategies for increasing interest on low cost healthy food. In particular the focus should be on improved collaboration on innovation adoption and marketing strategies, considering ROP consumers’ preferences and needs. An external political intervention is instead necessary to fill the knowledge and regulations’ gaps on healthy food issues.

Three “Bali Deliverables” for more Food Security

As the clock is ticking for a positive outcome at the Ninth WTO Ministerial Conference to be held in Bali in December 2013, agricultural negotiators are scrambling to find solutions to issues such as tariff-rate quota (TRQ) administration and export competition in order to improve trade flows. The main issue seems to be whether WTO rules applying to public stockpiles in developing countries need to be changed or temporarily suspended as a means to enhance national food security. This paper is based on a note submitted to the ICTSD-IPC Expert Group “Meeting on Agriculture and Food Security – Policy Options for MC9 and beyond” (Geneva, June 2013). It lists the policy instruments impacting on global, national and (urban and rural) household food security – “The Food Security Tool Box” – and asks which immediate decisions the WTO Ministers might take in this field despite the political difficulties such as continued agro-dumping practices or the “land grab” issue. Three such “deliverables” are outlined: (i) regional and “virtual” food security schemes could be allowed to provide reserves to other countries without violating the obligation to “form an integral part of a food security programme identified in national legislation” (Agreement on Agriculture, Annex II, para 3); (ii) TRQ under-fills could be improved by mandatory enquiries into low fill rate situations; and (iii) World Food Program (WFP) and other non-commercial food purchases could be exempted from export restrictions and prohibitions. High ambitions for Bali seem to be misplaced. A more realistic yet real progress could restore the dwindling credibility of the WTO as a forum for trade negotiations.

The WTO and Food Security: What’s Wrong with the Rules?

The WTO Agreement on Agriculture (AoA) is the predominant multilateral legal framework governing agricultural trade. The objective of the AoA is to liberalise trade in agriculture through reductions in tariffs, domestic support and export subsidies. The AoA has not, however, ‘levelled the playing field’ and has not resulted in the equitable distribution of food, particularly for the poorer developing countries. On the other hand, support for small farmers does not ensure food security for the poor. While food security has no simple solutions such as “free trade is good for you”, reform proposals for trade rules which only address agricultural policy instruments fail to account for consumer and other interests: neither tariff reductions and subsidy disciplines, nor safeguards and other measures of producer protection can automatically increase food security. Rather, what is needed is the full and proper implementation of a number of commitments which the international community has already entered into in various human rights treaties, but which even the envisaged results of the now failed Doha Round negotiations could not ensure without revisiting relevant multilateral trade and investment rules.

Action of food preservatives on 14-days dental biofilm formation, biofilm vitality and biofilm-derived enamel demineralisation in situ

AIMS The aims of this double-blind, controlled, crossover study were to assess the influence of food preservatives on in situ dental biofilm growth and vitality, and to evaluate their influence on the ability of dental biofilm to demineralize underlying enamel over a period of 14 days. MATERIALS AND METHODS Twenty volunteers wore appliances with six specimens each of bovine enamel to build up intra-oral biofilms. During four test cycles of 14 days, the subjects had to place the appliance in one of the assigned controls or active solutions twice a day for a minute: negative control 0.9 % saline, 0.1 % benzoate (BA), 0.1 % sorbate (SA) and 0.2 % chlorhexidine (CHX positive control). After 14 days, the biofilms on two of the slabs were stained to visualize vital and dead bacteria to assess biofilm thickness (BT) and bacterial vitality (BV). Further, slabs were taken to determine mineral loss (ML), by quantitative light-induced laser fluorescence (QLF) and transversal microradiography (TMR), moreover the lesion depths (LD). RESULTS Nineteen subjects completed all test cycles. Use of SA, BA and CHX resulted in a significantly reduced BV compared to NaCl (p < 0.001). Only CHX exerted a statistically significant retardation in BT as compared to saline. Differences between SA and BA were not significant (p > 0.05) for both parameters. TMR analysis revealed the highest LD values in the NaCl group (43.6 ± 44.2 μm) and the lowest with CHX (11.7 ± 39.4 μm), while SA (22.9 ± 45.2 μm) and BA (21.4 ± 38.5 μm) lay in between. Similarly for ML, the highest mean values of 128.1 ± 207.3 vol% μm were assessed for NaCl, the lowest for CHX (-16.8 ± 284.2 vol% μm), while SA and BA led to values of 83.2 ± 150.9 and 98.4 ± 191.2 vol% μm, respectively. With QLF for both controls, NaCl (-33.8 ± 101.3 mm(2) %) and CHX (-16.9 ± 69.9 mm(2) %), negative values were recorded reflecting a diminution of fluorescence, while positive values were found with SA (33.9 ± 158.2 mm(2) %) and BA (24.8 ± 118.0 mm(2) %) depicting a fluorescence gain. These differences were non-significant (p > 0.05). CONCLUSION The biofilm model permited the assessment of undisturbed oral biofilm formation influenced by antibacterial components under clinical conditions for a period of 14 days. An effect of BA and SA on the demineralization of enamel could be demonstrated by TMR and QLF, but these new findings have to be seen as a trend. As part of our daily diet, these preservatives exert an impact on the metabolism of the dental biofilm, and therefore may even influence demineralization processes of the underlying dental enamel in situ.

Foodborne illness - An age old problem requiring contemporary solutions

Foodborne illness has always been with us, and food safety is an increasingly important public health issue affecting populations worldwide. In the United States of America, foodborne illness strikes millions of people and kills thousands annually, costing our economy billions of dollars in medical care expense and lost productivity. The nature of food and foodborne illness has changed dramatically in the last century. The regulatory systems have evolved to better assure a safe food supply. The food production industry has invested heavily to meet regulatory requirement and to improve the safety of their products. Educational efforts have increased public awareness of safe food handling practices, empowering consumers to fulfill their food safety role. Despite the advances made, none of the Healthy People 2010 targets for reduction of foodborne pathogens has been reached. There is no single solution to eliminating pathogen contamination from all classes of food products. However, irradiation seems especially suited for certain higher-risk foods such as meat and poultry and its use should advance the goal of reducing foodborne illness by minimizing the presence of pathogenic organisms in the food supply. This technology has been studied extensively for over 50 years. The Food and Drug Administration has determined that food irradiation is safe for use as approved by the Agency. It is time to take action to educate consumers about the benefits of food irradiation. Consumer demand will compel industry to meet demand by investing in facilities and processes to assure a consistent supply of irradiated food products. ^