M.L. Castelló

Quality Characteristics, Respiration Rates, and Microbial Stability of Osmotically Treated Mango Tissue (Mangifera indica L.) with or without Calcium Lactate:

Mango minimally processed (20 °Brix) was obtained by applying osmotic treatments and the product quality development was evaluated throughout storage. Osmotic treatments were carried out at atmospheric pressure Osmotic dehydration (OD) and by applying a vacuum pulse osmotic dehydration (PVOD) using 45 °Brix sucrose solutions with and without calcium lactate (2%). Mechanical properties were measured after treatments and after 10 days storage. Color, microbial controls, and respiration rates were measured throughout storage time, in order to evaluate the development of the different parameters which affect product quality. Osmotic treatments induced changes in the physical properties, respiration rates and microbial behavior, depending on the treatment conditions and the addition of calcium lactate. From the microbiological point of view the most stable samples are those treated with calcium in both OD and PVOD treatments. Respiration rates were also reduced to a greater extent in these treatments. Mechanical properties are also better preserved when calcium is applied in PVOD treatments. Nevertheless, a greater decrease in hue is observed in calcium treated samples which indicates that browning occurs more intensely in these cases.

Mass Transfer and Volume Changes in French Fries During Air Frying

The production of healthier fried foods requires the adaptation of industrial processes. In this context, air frying is an alternative to deep oil frying to obtain French fries with lower fat content. Kinetic analysis of compositional changes and main fluxes involved in air frying were carried out, and the results were compared to those obtained for deep oil frying. The influence of the type of sample (unpretreated, frozen, or blanched potatoes) was also analyzed. The results showed that oil uptake is much lower in air frying although a much longer processing time is required. Also, water loss and thus the loss of volume were much higher in air frying compared to the conventional process.

Influence of thermal treatment and storage on astringency and quality of a spreadable product from persimmon fruit

The aim of this work was to develop osmodehydrated products from cubes of persimmon (var. Rojo Brillante), which could be spread as a jam but keeping the typical aroma, flavour and colour of fresh fruit. The application of a thermal treatment in the filling stage has been studied, with or without a later pasteurisation step at 90°C for 20min. These spreadable products were stored at room temperature or in refrigeration. The chemical composition, pH, aw, colour, astringency, antioxidant capacity and the growth of yeast, moulds and aerobic mesophiles were analysed after the manufacture process and throughout the storage (approximately 3.5months). Sensorial analyses were also performed after 24h of being prepared and after 49days of refrigeration. The product obtained without thermal treatment was the best since it maintained the characteristic persimmon colour better and showed higher antioxidant capacity. Furthermore, it was the best, according to the panel, not only for appearance but also for flavour.

Physicochemical characteristics of citrus jelly with non cariogenic and functional sweeteners

AbstractIn this study the effect of sweeteners with low glycemic index and non-cariogenic characteristics (isomaltulose, oligofructose and tagatose) in jelly prepared with citrus juice has been evaluated considering a citrus jelly formulated with sucrose as reference. The soluble solids, moisture content, pH, water activity, antioxidant capacity, optical and mechanical properties of jelly made using different sweeteners was determined during storage. Besides, mesophilic aerobics and moulds and yeasts was also counted to determine their stability over time. Sensory evaluation of the citrus jelly has also been done. The results showed the antioxidant activity decreased during storage in all formulations. Tagatose increased lightness whereas coordinates a*, b* and chrome of all the jellies prepared using new sweeteners were lower than jellies with sucrose. However, citrus jelly with only oligofructose or tagatose or with the mixture of isomaltulose and tagatose were most closely resembled to the control jelly with respect to mechanical properties. Jelly prepared with the combination of isomaltulose and tagatose in equal proportions obtained the best score in the sensorial analysis.

Washing of cut persimmon with thyme or lemon essential oils

The aim of this study was to develop a minimally processed persimmon product by applying different concentrations of thyme essential oil or lemon essential oil on the product in order to increase its shelf life. Essential oils were applied on cut persimmon in a preliminary stage of immersion, and the samples were then stored at 4 ℃ for seven days. Moisture content, soluble solids content, antioxidant capacity, total phenols, pH, optical and mechanical properties and microbiology counts were periodically analysed. Noteworthy was that the application of thyme essential oil in the washing stage improved the preservation of the fruits’ colour. All samples would be considered safe according to microbiology requirements and based on the period of study, regardless of the type of essential oil applied.

Influence of calcium lactate and modified atmosphere on respiration rate, optical and mechanical properties of sliced persimmon

The aim of this study was to evaluate the effect of a modified atmosphere (5% and 10% of CO2) and calcium lactate treatment on the respiratory metabolism of minimally processed persimmon. A static system to measure changes in the composition of the headspace was used. Composition, texture and colour were also analysed. Persimmon slices were evaluated immediately after the washing treatment and after the O2 composition had decreased to 17% to avoid changes in the metabolic pathway. All samples were stored at 4 ℃. The results showed that modified atmosphere did not affect compositional properties, although there was a slight increase in pH values at the end of each treatment. Calcium lactate treatment reduced the respiration rate, in terms of O2, in samples kept in air. Additionally, a calcium lactate effect was immediately observed on mechanical properties after the washing stage. On the other hand, luminosity and b* coordinate decreased in unwashed and calcium lactate samples kept in 5% CO2.

Influence of Low Glycaemic Index Sweeteners on Antioxidant, Sensory, Mechanical, and Physicochemical Properties of a Watermelon Jelly

The replacement of sucrose by new noncariogenic and low glycaemic index sweeteners (isomaltulose and tagatose) and the addition of natural watermelon juice in jelly have been assessed in terms of composition, texture, colour, antioxidant activity, microbiology, and sensory properties. These analyses were performed initially and after 15 days of storage. Furthermore, the values were compared with those obtained in the analyses of a commercial watermelon jelly. The results showed that the antioxidant activity increased with the storage time in the control sample and in samples combining isomaltulose and tagatose. In addition, noncariogenic and low glycaemic index sweeteners did not affect the instrumental texture. However, the colour changed, especially in the sample containing tagatose only. Finally, the dessert containing tagatose and isomaltulose in equal proportion achieved a similar score in the sensory evaluation as the commercial one, showing the feasibility of using these sweeteners to reformulate watermelon jelly.

Influence of drying process and particle size of persimmon fibre on its physicochemical, antioxidant, hydration and emulsifying properties

Persimmon, given its current surplus production, could be an alternative source for the extraction of certain interesting ingredients for the food industry and human health, such as fibre. Thus, the aim of this study was to analyse the influence of hot air and freeze-drying, as well as the particle size of fibre extracted from persimmon peels or pulp on their physicochemical, antioxidant, hydration and emulsifying properties, compared to commercial fibres (from peach, lemon, orange and apple). The results showed that both freeze-dried persimmon pulp and freeze-dried peel had better hydration properties and oil holding capacity than other fibres analysed, although the swelling capacity was higher for lemon fibre. Freeze-dried persimmon peel fibre showed higher values of emulsion stability than commercial fibres. Finally, the antioxidant activity of the smallest sized persimmon peel fibre obtained by freeze-drying was higher than that for lemon, orange and peach fibre.

Influence of preharvest treatments to reduce the seasonality of persimmon production on color, texture and antioxidant properties during storage

Persimmon production has increased considerably, thanks to techniques for removing astringency whilst maintaining the strong consistency. Currently, the needs of cooperatives are focused on increasing the commercial period. Thus, the aim of this study was to analyze the effect of preharvest treatments (paclobutrazol (PBZ) and Ethephon to accelerate ripening and GA3 to delay it) on persimmon size, composition, color index (CI), texture and antioxidant properties over 11 days of postharvest storage at 4ºC. The results showed that the size of fruits subjected to preharvest treatment was smaller than in untreated fruit. Moreover, CI of the apical zone was higher in samples of standard ripening throughout the first few days of storage. It is also noteworthy that the treated fruits at the beginning of storage reported greater antioxidant properties. Finally, the evolution of the antioxidants has been fitted with a first-order model to predict their kinetic degradation depending on the persimmon harvest period.

Effect of replacing sucrose with tagatose and isomaltulose in Mandarin orange marmalade on rheology, colour, antioxidant activity, and sensory properties

The aim of this study was to make mandarin orange marmalades, in which sucrose is replaced by sweeteners, such as tagatose and isomaltulose, which are non-cariogenic and have a low glycemic index. Analyses of rheology, colour, antioxidant activity, microbiology, and sensory properties were carried out on marmalades on their first day, and after 90, 180, and 360 days of storage. The results showed that marmalades made with healthy sweeteners had a less elastic character and were thinner in consistency than those made with sucrose. Lightness was shown to be highest in mandarin orange marmalades made with tagatose, although colour was stable for 180 days to one year of storage. Tagatose also enhanced the antioxidant activity of these marmalades. All marmalades were microbiologically stable. Finally, marmalades made with tagatose alone scored the highest for global acceptance and intention of buying by consumers.