Gluten-Free Pasta—Advances in Research and Commercialization
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Gluten-free Pasta—Advances in Research and Commercialization ated a demand for products made from while none of the commercial pastas A.-S. Hager, E. Zannini, and raw materials other than wheat, rye, and screened contained egg products or milk E. K. Arendt1 barley, all of which contain gluten. The proteins. Pea protein was used in two of School of Food and Nutritional utilization of rice (13) and corn (8,17) for the commercial brands (Gerblé and Schär) Sciences, University College Cork the production of pasta has been well re- screened. searched and are the most commonly used A satisfactory pasta product is charac- Cork, Ireland gluten-free ingredients in the food indus- terized by a uniform color and smooth try: 22 of the 33 commercial products surface, mechanically strong strands, and ue to its ease of preparation, palat- screened in this study contained rice, and low matter loss during cooking. Because ability, versatility, low cost, nutritional D 20 of 33 products contained corn. Other these properties are often not satisfactory value, and long shelf life, pasta is an ex- less well-researched gluten-free raw mate- when using gluten-free cereals, as opposed tremely popular commercial food product. rials used for pasta production include the to wheat semolina, additives such as emul- Pasta products are commonly produced by pseudocereals quinoa (3), buckwheat (1), sifiers may be employed. The fatty nature extrusion, and their main ingredients are and amaranth (20). Of the 33 commercial of emulsifiers enables them to act as a durum wheat semolina and water. Celiac products screened in this study, only 1 lubricant in the extrusion process, result- disease is an immune-mediated disease contained quinoa and 1 contained buck- ing in less nozzle wear and making pro- triggered by the ingestion of the protein wheat. Despite the high nutritional quality duction easier. They can also provide a composite gluten. The only treatment for of buckwheat, its use is limited due to its firmer consistency, a less sticky surface, celiac disease is the permanent exclusion higher price compared with corn and rice, and better starch retention properties dur- of sources of gluten (wheat, rye, and barley as well as its dark color and strong flavor. ing cooking (13). Regarding the samples products) from the diet. It is important, Amaranth was not found in the commer- screened in this study, 39% contained therefore, that high-quality cereal products cial products screened in this study. Chillo mono- and diglycerides of fatty acids made from alternative grains are available et al. (5) reported that the use of amaranth (E471). Several authors have reported that to this segment of the popultion. Recently, flour alone in pasta presented remarkable pregelatinization of starch-rich ingredients research on the development and improve- difficulties in the extrusion phase. How- can improve the functional properties and ment of gluten-free pasta has intensified. ever, the incorporation of quinoa, chick- provide body and texture in a product At the same time, the number of gluten- pea, and broad bean flour improved ama- (17). Although production of pasta con- free pasta products available on the market ranth pasta, and the resulting products taining oat or quinoa flour alone failed, has increased dramatically. demonstrated excellent cooking perfor- Chillo et al. (4) obtained acceptable results There is some question as to whether mance, as well as sensory properties (6). with the addition of pregelatinized starch the findings of food scientists are well The majority of pasta products screened in as a structuring agent. Portions of the reflected in available gluten-free prod- this study contained a mixture of the flours were heated to 80°C, cooled, and ucts. This article presents an overview of abovementioned gluten-free raw materi- added to the flour-water mixture. Among the outcomes of recent studies and of the als. The use of a mixture of materials bal- the commercial products reviewed, only composition and quality of commercial ances out the sensorial deficits of single one (Gerblé) label stated that precooked gluten-free pasta samples. Samples of 33 flours and helps compensate for their maize flour was an ingredient. Other pasta products sold as “gluten-free pasta” technological shortcomings. products screened may also contain modi- were screened in this study. The samples Apart from gluten-free grains, nonce- fied starches, because starches altered by were sourced from eight European coun- real sources have also been considered for physical means or enzymes may be labeled tries (Austria, Finland, France, Germany, the production of pasta. Some commercial simply as “starch” rather than with a spe- Ireland, Italy, Portugal, and Sweden). For pasta products contain chickpea and lupin cific name. However, this designation comparison, an Italian brand of wheat pas- flours, as well as potato flour. Response must be complemented by the indication ta (DeCecco) was included in the study. surface methodology was used by Singh et of its origin if the source may contain glu- al. (21) to develop a formulation based on ten (9). Another well-researched group of Selection of Gluten-free Raw Materials sweetpotato and soy flours. Schoenlechner ingredients, hydrocolloids, were not found Celiac disease is a lifelong immune dis- et al. (20) replaced 3% of amaranth, qui- in the commercial products screened. order in which parts of the small intestine noa, or buckwheat flour with egg white However, studies have shown that the in- are damaged or destroyed by the immune powder, soy protein isolate, and casein. corporation of polysaccharides such as system in reaction to ingestion of gluten. With regard to textural characteristics and xanthan, carboxymethylcellulose, locust Currently, the only treatment for celiac cooking loss, egg white powder was supe- bean, or guar gum can result in pasta with disease is a gluten-free diet. The dietary rior. Soy protein and casein addition led to improved sensory characteristics (12,18). requirements of celiac patients have cre- products that disintegrated faster during cooking, indicating a weaker dough ma- Challenges in Gluten-free Pasta 1 Corresponding author. E-mail: [email protected]; Tel: 00353 trix. Chillo et al. (7) also observed a nega- Production 214902064; Fax: 00353 214270213. tive effect of casein on pasta quality. One Pasta is a collective term used to de- http://dx.doi.org/10.1094/CFW-57-5-0225 of the commercial brands (Semper) scribe products such as macaroni, spa- ©2012 AACC International, Inc. screened in this study contained soy flour, ghetti, lasagna sheets, and fettuccine. Its CEREAL FOODS WORLD / 225 production involves mixing, kneading, with a long shelf life, a drying step is nec- firmness of the wheat control sample was extrusion, shaping, and drying. Although essary. The moisture content of fresh pasta 503 g, while the gluten-free samples the use of rice for the formulation of noo- as it emerges from the die is ≈30%. During ranged from 149 to 1,264 g. Regarding dles has been well studied, literature on drying, the moisture content must be re- elasticity, gluten-free samples ranged from the formulation of pasta from gluten-free duced to <12.5% in such a way that the 11 to 71 g and only 8 of 33 samples had raw materials is scarce. The main differ- complex protein and starch structure re- values higher or equal to those for the ence between noodle and pasta processing mains unchanged and cracking and other wheat pasta sample (45 g). is that the traditional process for making physical defects are avoided (2). A common problem regarding gluten- noodles involves several heating and cool- The production of cereal-based prod- free pasta is the stickiness of the cooked ing steps aimed at reorganization of the ucts from nonwheat sources presents a product. During production of wheat pas- starch matrix (14), while pasta processing major technological challenge. To over- ta, a gluten layer is formed that entraps the consists of a simple extrusion step. Con- come this hurdle, researchers and product starch granules (19). A weak or discon- ventional wheat pasta is usually produced developers have focused mainly on the tinuous protein matrix, as is found in glu- from durum semolina, a granular product search for appropriate ingredients and ten-free products, permits starch to leach achieved through a special grain-milling additives suitable for the production of a out during the cooking process, and the process. According to the publications cohesive structure. However, more focus resulting cooked pasta becomes sticky. reviewed, gluten-free pasta is usually should be placed on the role of processing Figure 1 shows commercial wheat and made from flour rather than semolina. conditions that will promote starch orga- gluten-free spaghettis. While the wheat This can be explained by the fact that the nization that is able to substitute for a glu- spaghetti shows a continuous outer layer availability of gluten-free raw materials in ten network in the final product. Marti et several micrometers thick, this layer is not general is limited, as is the production of al. (15,16), for example, compared conven- observed in the gluten-free sample, which gluten-free semolina. tional extrusion at 50°C with extrusion results in increased cooking loss and stick- The significantly smaller particle size cooking (115°C) and found that the latter iness. Stickiness values for the commercial found in flour can cause thermal stresses improved the cooking quality of rice- gluten-free pasta samples varied widely during pasta manufacture that may cause based pasta. Cooling cycles, as utilized in from 10 to 55 g. The value for the com- protein denaturation (2); in addition, hy- rice noodle making, can lead to starch mercial wheat pasta sample was 22.93 g. dration during the mixing step is different.