Chemical and microbiological characterization of Portuguese varieties of pears.

The sun-dried pears of the local variety known as S. Bartolomeu , found in the centre of Portugal, are relatively small fruits, characterized by an intense reddish brown colour, that loose their pronounced astringency with drying. However, and since their production has been declining over the past decades, there has been an increasing interest in drying also for other varieties of pears, also with small dimensions, as an alternative to produce the dried pears. The aim of this work is the evaluation of the nutritional properties of fresh and dried pears of the local varieties known as Amendoa, Amorim, Carapinheira Branca and S. Bartolomeu , all original from of the centre of Portugal. The results enable us to conclude that the fresh pear pulp of all varieties has a low content of protein and a high level of total sugars, as is generally true for fruit. However, their values of dietary fiber ranged between 12 and 15% (dry mass) constituting these pears a potential source of dietary fibre. In addition, it is also possible to conclude that, apparently, the solar stove-drying process has no effect on the nutritional characteristics of the pears, except on total sugars and acidity. The range of water activity values and microbial charge of the different pears also allow inferring that the dried fruits obtained from the four varieties studied are potentially safe from a microbiological point of view. The resemblance in the characteristics of the fruits, together with the similarity of behaviour towards drying, suggests that the fruits of the varieties Carapinheira Branca, Amendoa and Amorim can be viewed as a good alternative to those of the variety S. Bartolomeu for the production of dried pears.

[1]  F. Figuerola,et al.  Fibre concentrates from apple pomace and citrus peel as potential fibre sources for food enrichment , 2005 .

[2]  P. Ramulu,et al.  Total, insoluble and soluble dietary fiber contents of Indian fruits , 2003 .

[3]  O. Paredes-López,et al.  Chemical and biochemical changes in prickly pears with different ripening behaviour. , 2003, Die Nahrung.

[4]  C. Chau,et al.  Comparison of the chemical composition and physicochemical properties of different fibers prepared from the peel of Citrus sinensis L. Cv. Liucheng. , 2003, Journal of agricultural and food chemistry.

[5]  E. Sendra,et al.  Effect of Storage Conditions on Quality Characteristics of Bologna Sausages Made with Citrus Fiber , 2003 .

[6]  R. Guiné,et al.  Analysis of Moisture Content and Density of Pears During Drying , 2003 .

[7]  A. Lojek,et al.  Comparative content of some bioactive compounds in apples, peaches and pears and their influence on lipids and antioxidant capacity in rats. , 2002, The Journal of nutritional biochemistry.

[8]  José A. Castro,et al.  PEAR DRYING PROCESS ANALYSIS: DRYING RATES AND EVOLUTION OF WATER AND SUGAR CONCENTRATIONS IN SPACE AND TIME , 2002 .

[9]  Ivonne Delgadillo,et al.  Composition of phenolic compounds in a Portuguese pear (Pyrus communis L. var. S. Bartolomeu) and changes after sun-drying. , 2002, Journal of agricultural and food chemistry.

[10]  L. Jaime,et al.  Structural carbohydrate differences and potential source of dietary fiber of onion (Allium cepa L.) tissues. , 2002, Journal of agricultural and food chemistry.

[11]  António S. Barros,et al.  Use of FT-IR spectroscopy to follow the effect of processing in cell wall polysaccharide extracts of a sun-dried pear , 2001 .

[12]  O. Martín‐Belloso,et al.  Characterization of dietary fiber from orange juice extraction , 1998 .

[13]  C. M. Bourgeois,et al.  Dietary fibres: Nutritional and technological interest , 1997 .

[14]  Keith W. Waldron,et al.  Dietary fiber content of pear and kiwi pomaces , 1995 .

[15]  N. Asp,et al.  Determination of insoluble, soluble, and total dietary fiber in foods and food products: interlaboratory study. , 1988, Journal - Association of Official Analytical Chemists.

[16]  G. Spiller CRC Handbook of Dietary Fiber in Human Nutrition, Third Edition , 1986 .

[17]  W. Baltes Chemical changes in food by the maillard reaction , 1982 .

[18]  W. Horwitz Official Methods of Analysis , 1980 .

[19]  Dulcineia Ferreira Estudo das transformações bioquímicas e químicas da pêra de S. Bartolomeu durante o processo de secagem – recurso endógeno da região de Viseu , 2003 .

[20]  K. J. Park,et al.  Drying of pear d’Anjou with and without osmotic dehydration , 2003 .

[21]  L. Mckee,et al.  Underutilized sources of dietary fiber: A review , 2000, Plant foods for human nutrition.

[22]  B. Bartolomé,et al.  Nature of the condensed tannins present in the dietary fibre fractions in foods , 1995 .

[23]  P. Kumar,et al.  Changes in the physico-chemical and biochemical compositions of custard apple (Annona squamosa L.) fruits during growth, development and ripening , 1995 .

[24]  A. J. Mcevily,et al.  Inhibition of enzymatic browning in apple products by 4-hexylresorcinol , 1995 .

[25]  D. A. Arias,et al.  Tables de Composicion de Alimentos , 1987 .