M.M. Camacho

Iron deficiency and iron fortified foods—a review

Abstract Iron is a mineral that is necessary for producing red blood cells and for redox processes. Iron deficiency is considered to be the commonest worldwide nutritional deficiency and affects approximately 20% of the world population. Lack of iron may lead to unusual tiredness, shortness of breath, a decrease in physical performance, and learning problems in children and adults, and may increase your chance of getting an infection. This deficiency is partly induced by plant-based diets, containing low levels of poorly bio-available iron. The most effective technological approaches to combat iron deficiency in developing countries include supplementation targeted to high risk groups combined with a program of food fortification and dietary strategies designed to maximize the bio-availability of both the added and the intrinsic food iron. In this paper, different aspects related to iron-fortified foods is reviewed. These include used iron compounds, considering its bioavailability and organoleptic problems, food vehicles and possible interactions.

Jam manufacture with osmodehydrated fruit

Abstract Jams are made from fruit and sugar mixed in proportions so that the final product contains a minimum fruit content of 30% and 45°Brix minimum. Traditional manufacturing methods require concentration by heat treatments, which promotes quality changes that affect sensory and nutritional properties, the latter related mainly to ascorbic acid losses. An alternative to concentration is to incorporate previously dehydrated fruit, avoiding thermal treatment. Osmotic dehydration with sugar solutions has been described as a suitable method for preserving fruit quality to a great extent. On the other hand, osmotic solution becomes enriched with water-soluble fruit components after osmotic treatment. In this work, the production of kiwi and orange jam by using osmotically dehydrated fruits mixed with osmotic solution, without thermal treatment, has been studied. Physical (colour and mechanical properties) and physico-chemical properties (aw, °Brix, moisture content, pH, acidity) of obtained products have been analysed and compared with those determined for commercial available products.

Effect of Thermal Treatment and Storage Conditions on the Physical and Sensory Properties of Grapefruit Juice

Physical parameters, such as particle size distribution, flow behavior, density, turbidity, and color, were measured and sensory evaluation was carried out to compare the properties of freshly squeezed grapefruit juice with those of juice that has been pasteurized by microwave or by following a conventional heating method. Samples were either frozen-stored or refrigerated. In general, the physical parameters of grapefruit juice were significantly affected by heat treatment, especially in the case of the conventional process. However, from a sensory point of view, pasteurized samples were similar to fresh ones. When frozen, turbidity, particle size distribution, density, flow behavior, and color were stable throughout the studied period, regardless of the pasteurization treatment. During refrigerated storage, the turbidity, particle size distribution, and consistency index decrease. This occurs in a more pronounced way in the case of juice which has not been submitted to a heating treatment, probably due to residual pectin methyl esterase activity. Furthermore, the association between the carboxyl groups of pectin chains and Ca2+ could be responsible for both the subsequent increase in the turbidity of the juice and also the decrease in its density. Throughout the period under study, the smallest color change was experienced by microwave-pasteurized juice. For these reasons, and also due to the reduction in the process time, microwave treatment can be recommended as a method for the pasteurization of grapefruit juice.

Physicochemical and Sensorial Properties of Grapefruit Jams as Affected by Processing

Jam is an effective and tasty way of preserving fruit. Jam processing procedures as well as storage conditions and duration are important factors for jam quality. Traditional jam processing involves the application of severe thermal treatments that imply undesirable changes in the product quality characteristics such as colour, texture, flavour and nutritional and functional value. In this work, osmotic dehydration (OD) and/or microwave energy (MW) was proven as adequate to obtain jam with the typical characteristics of water content, degree Brix, pH and water activity of jam obtained by conventional thermal heating. The sensory evaluation carried out to compare the product showed that samples submitted to more intense heating treatments (conventional or MW) had significantly higher scores in colour saturation, brightness, grapefruit taste and extensibility than OD or OD+MW ones. As deduced from the obtained results, OD treatment prevents grapefruit colour changes, and mild MW heating contributes to increase the consistency and decrease the extensibility of the obtained jam. In this way, OD+MW jam was preferred by assessors mainly due to its higher consistency. The sample obtained by this procedure was stable during storage.

Effect of process technology on the nutritional, functional, and physical quality of grapefruit powder.

The health properties of fruit are widely known. Powdered fruit may be a practical format to be offered to the consumer. Nevertheless, the process used to obtain the powder must ensure the maximum retention of the bioactive compounds and the functional value of the fruit while retaining adequate physical properties. The aim of this study was to compare freeze-drying and spray drying as the drying technologies to obtain grapefruit powder. The obtained results allow freeze-drying to be proposed as a better technology than spray drying in order to obtain a product with a higher content of vitamin C and total carotenoids. Moreover, all of the edible part of the fruit is used in this case, so a greater quantity of healthy compounds is preserved and by-product generation is avoided. Adding about 6 g water, 4 g Arabic gum and 0.6 g bamboo fibre/100 g grapefruit pulp is recommended before freeze-drying.

Production of Raisins and its Impact on Active Compounds

Phenolic compounds, together with ascorbic acid and some other bioactive compounds, have been linked with the health-promoting effects of grapes, mainly due to their antioxidant capacity. Despite the fact that the different processes carried out to obtain fruit products could affect their bioactive content, the process applied in this work to obtain raisins and canned grapes have not shown undesirable effects. In fact, the use of microwaves instead of hot air not only promotes the antioxidant capacity of raisins, but also the antioxidant capacity of the product.

Combined Drying Technologies for High-Quality Kiwifruit Powder Production

Freeze-drying is a dehydration technique which, from a sensory, nutritional and functional point of view, provides high-quality powder products. Nevertheless, both long processing times and high economic costs are required. In this study, pre-drying the samples using hot air or microwave has been considered in order to reduce the initial product’s water content thereby shortening the freeze-drying time so as to obtain high value products at a reduced cost. The effect of dehydration pre-treatments on the kinetics, antioxidant activity and solubility of freeze-dried kiwifruit products was evaluated. Nine different thin-layer semi-theoretical models were used to fit the drying data. According to the obtained results, the pre-treated samples exhibited higher drying rates than the fresh sample. In turn, the dehydration pre-treatments used did not affect the solubility or the antioxidant activity of the samples.

EFFECTS OF BLANCHING ON GRAPES (VITIS VINIFERA) AND CHANGES DURING STORAGE IN SYRUP

The authors thank the Ministerio de Educacion y Ciencia, the Fondo Europeo de Desarrollo Regional and the Conselleria de Educacion y Ciencia for the financial support given throughout the Projects (AGL 2005-05994 and GV04A-394 AGL 2005-05994). The translation of this paper was funded by the Universidad Politecnica de Valencia, Spain.

Stability of micronutrients and phytochemicals of grapefruit jam as affected by the obtention process.

Fruits are widely revered for their micronutrient properties. They serve as a primary source of vitamins and minerals as well as of natural phytonutrients with antioxidant properties. Jam constitutes an interesting way to preserve fruit. Traditionally, this product is obtained by intense heat treatment that may cause irreversible loss of these bioactive compounds responsible for the health-related properties of fruits. In this work, different grapefruit jams obtained by conventional, osmotic dehydration (OD) without thermal treatment and/or microwave (MW) techniques were compared in terms of their vitamin, organic acid and phytochemical content and their stability through three months of storage. If compared with heating, osmotic treatments lead to a greater loss of organic acids and vitamin C during both processing and storage. MW treatments permit jam to be obtained which has a similar nutritional and functional value than that obtained when using a conventional heating method, but in a much shorter time.

Impact of Temperature, Gum Arabic and Carboxymethyl Cellulose on Some Physical Properties of Spray-Dried Grapefruit

Abstract Spray-dried fruit powder may be an interesting alternative for the purposes of promoting fruit consumption among consumers. The use of carrier agents is especially necessary for the production of spray-dried fruit powders. As they may affect some physical properties of the powder, it is important to adjust the amount at which they have to be added to the minimum in order to achieve the necessary effects. The final aim of the study was to identify the most suitable atomization temperature, as well as the optimal concentration of gum Arabic (GA) and carboxymethyl cellulose (CMC) to be used as carriers, in order to obtain grapefruit powder with the maximum dry matter yield (DMY) and porosity, the minimum water content and, simultaneously, with suitable color characteristics. The results of the study don’t recommend the use of CMC and suggest that the best color, the one that corresponds to a free-flowing powder, corresponds to a very luminous one, low in chroma and with a hue that is much more yellow than reddish orange.