METHOD FOR CONTROLLING AND STANDARDIZING THE PRODUCTION OF TRADITIONAL PASTA BY USING GRAS MICROORGANISMS.
Brief description of the invention
The object of the present invention is a method for standardising and controlling the production of traditional pasta through the use of a mixture of microorganisms generally recognised as safe (GRAS microorganisms). Such method allows the attainment of the typical organoleptic characteristics (aroma and texture) of pasta obtained using traditional processes, more rapidly and with greater efficiency.
State of the art
Italy, the global leader in pasta manufacture and for its per-capita consumption, has a thriving industry which transforms the raw ingredient, consisting of durum wheat, into durum wheat flour and then into pasta. This objective has been achieved thanks to modern durum wheat flour processing technology for pasta production, with reduced processing times (the use of finer granulometry flour in order to reduce hydration times and the use of tepid water in the dough making process) and drying times (by using higher frequency high, and very high temperature drying cycles). Frequently, the product produced using this technology is a very standardised product, meeting only some of the typical organoleptic requirements for pasta (5). Good quality pasta must meet precise organoleptic characteristics: amber yellow colour at the time of purchase, "al dente" consistency, the absence of any surface tackiness at the time of tasting (6) and finally, a characteristic aroma. Some of these requirements have been fully satisfied by genetic improvement work on durum wheat over recent years, leading to the establishment of varieties with high
technological value (7). The sophisticated demands of modern consumers are driving research towards other objectives, such as elevation of the aromas the pasta takes on during extrusion and during the drying process, and the preservation of nutritional properties. Indeed, this is the main characteristic of the pastas produced by hand in small scale pasta factories, where drying tasks place over much longer times, using low temperature thermal drying cycles. The standardisation of industrial manufacturing output will allow the attainment of significant results, also in relation to the salubrity and dietary safety of traditional pasta. Indeed, it is known that during drying for long periods of time and at low temperatures, dangerous microbiological contamination can occur, which it is essential to prevent or even eliminate. Some indications, both from recent publications appearing in specialised journals, and from conference presentations (1-3) have highlighted the role certain microorganisms and enzymes might play in pasta production (especially the handmade types); through their specific activities, such microorganisms may contribute towards the production of particular aromas, and the improvement of the properties of the pasta. On the other hand, it is enough to simply refer to what occurs in a very closely related manufacturing field, that of bread making, to be aware of the fundamental role played by microorganisms and enzymes (U.S. 3,520,702) on the quality of the finished product. Present simultaneously in the dough, deriving from the flour-water mixture, are various species of microorganisms, predominantly represented by the yeasts and lactic acid bacteria. Predominant among the yeasts are the two genuses: Saccharomyces and Candida. S. cerevisiae is the predominant species in the yeast population, but S. exiguus and its anascosporogen form Candida holmii, C. milleri, C. robusta (the anascosporogen form of S. cerevisiae), C. krusei, C. stellata. Other genuses which may also be
found include Torulaspora, Pichia, Hansenula, Cryptococcus, Oosporidinm, Geotrichum, Endomycopsis, Rhodotorula, Schizosaccharomyces (8, 9). In dough, besides yeasts, also the homo- and heterofermentative lactic acid bacteria (Leuconostoc spp, Lactobacillus plantarum, Lb. brevis, Lb. fermentum, Lb. sanfrancisco etc.) (10, 11) and other microorganisms such as enterococci, micrococci, streptococci and bacillus spp. play an important role in conferring organoleptic characteristics, such as acidity, elasticity and aroma. During kneading, this lactic acid microflora quickly gains the upper hand over the initial flour bacterial flora (enterobacteria, Bacillus, Lactobacillus, Streptococcus, Micrococcus). Indeed, thanks to the production of lactic acid and acetic acid, the lactic acid bacteria inhibit facultative Gram" aerobes and anaerobes, Gram+ cocci and sporulating Gram+ bacilli. Among the activities of interest of such microorganisms, they break down proteins, making them more digestible and contribute towards the development of aromas through their fermentation products, esters, aldehydes, fatty acids etc. (Even so, the enzymes naturally present in flour have an important role to play in the manufacturing process, but vary significantly in quantity and activity, depending on the type of wheat grown, the climatic conditions and the cultivation and harvesting methods). The microbial population in the durum wheat flour mixtures used for pasta production is normally very low, and varies according to the variety of wheat used, the cultivation conditions and the weather conditions to which the crop is exposed. This variability is also found in the finished product, the pasta, which displays different organoleptic characteristics, developed by the microbial population during the drying process, depending on the conditions in which the raw material is used. This state of affairs is particularly evident when referring to pasta production using traditional methods involving low
temperatures and long drying times, operations which are performed precisely to promote the development of "typical" organoleptic characteristics.
Detailed description of the invention
The object of the present invention is a method for controlling and standardising the production of traditional pasta comprising the addition of a mixture of microorganisms to the dough prior to processing.
Surprisingly, the addition of selected and characterised GRAS microorganisms to the dough prior to processing avoids the above mentioned prejudicial effects, and consequently standardises the production, particularly for typical pasta. This process allows reduced drying times and operation at relatively high temperatures, since one is able to obtain the typical organoleptic characteristics (aromas and texture) of pasta obtained using traditional processes, more rapidly and with greater efficiency. Furthermore, the establishment of an expedient microflora impedes the initiation of any atypical or harmful fermentation reactions in the dough which might compromise product salubrity.
Among the isolated GRAS strains which may be adapted to being mixed in order to obtain the required results may be cited: lactobacilli, yeasts, enterococci, bacilli and micrococci in mixtures thereof.
Preferred microorganisms for obtaining a useful mixture for achieving the effects described include:
Yeasts:
Saccharomyces cerevisiae, Saccharomyces exiguus, Saccharomyces bayanus, Saccharomyces pastorianus, Candida humilis, Candida milleri, Candida holmii, Candida norvegensis, Candida boidinii, Hansenula anomala.
Microbes:
Lactobacillus sanfranciscensis , Lactobacillus brevis, Lactobacillus alimentarius,
Lactobacillus plantarus, Lactobacillus fermentum, Lactobacillus pontis,
Pediococcus pentosaceus, Leuconostoc mesenteroides, Weissella confusa,
Leuconostoc lactis, Micrococcus spp., Bacillus spp., Enterococcus spp.
Materials and methods
The GRAS strains used have been isolated from pasta factories operating according to the traditional production system at low temperature and with long drying times.
The strains have been selected and tested, on the basis of the enzyme activities expressed, for use for the formulation of biological coadjuvants and in industrial pasta production processes, in order to define normal conditions of use.
Strains gave been characterised genotypically using techniques such as those used for bacteria: RAPD-PCR (Randomly amplified polymorphic DNA) and by amplifying and sequencing the gene encoding 16S ribosomal RNA (16S rDNA).
For yeast strains, molecular profiles have been determined by means of random analysis (DD-PCR) on cDNA synthesised from mRNA (messenger RNA).
The method may be performed as follows:
Example
Abbreviations: CBS: Yeasts from the strain collection (Centraalbureau voor
Schimmelcultures) The Netherlands. ATCC: American Type Culture Collection.
Having prepared the mixture using the desired proportions of water and flour 1% of the following microorganism mixture is added:
Lactobacillus sanfranciscensis (ATCC N 43332)
Lactobacillus sanfranciscensis (ATCC N 43347)
Lactobacillus pontis (ATCC N0 51519)
Lactobacillus sanfranciscensis (ATCC N 27651)
Lactobacillus pontis (ATCC N° 51519)
Saccharomyces cerevisiae (CBS N0 1172)
Saccharomyces exiguus (CBS N° 379)
Candida boidinii (CBS N° 6990) having obtained a microbial concentration of 106 in the mixture; proceed with the drawing/extrusion and rapid drying. The pasta thus obtained has the same organoleptic characteristics as the best pasta made by hand, using a slow drying process.
Bibliography
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