Besides these effects, FOS can also have several technological roles when added to bakery products doughs: they can be easily added to foods where the prebiotic-probiotic combination is used (e.g. dairy products as yogurts and fermented milks), but also to beverages and bakery products. For the latter, they are ideal since they can withstand high temperatures. In the case of low-calories foods (“light”), with reduced amount of sugar, FOS are able to add to the sweetness of the product (especially the short chain FOS) without increasing the calories content, and/or can help mask the unpleasant aftertaste of any added sweetener. Many cereal’s flours, in particular wheat and rye, already contain a certain level of FOS; in order to increase it, it is possible to add to bakery products FOS extracted from naturally rich sources, as chicory and topinambur roots.
Recent guidelines recommend the daily consumption of 20 to 40 g of fibres, necessary to guarantee good bowel functionality and other healthy functions (e.g. reduction of cholesterol absorption and of post-meal glycemia), but it is estimated that the great majority of population can barely cover half of this amount. Fibers also have the beneficial effect of counteract overweight and obesity thanks to the long last satiety feeling that they can boost after meals. For all these reasons, fibres-rich foods like wholemeal bakery products, once considered for the less wealthy population, are now appreciated more and more and seeing non-stop market expansion. Wholegrain products alone (representing only a part of fibre-rich products) count thousands of products on the market, and marketing of new products has increased from ca. 200 in the year 2000 to over 3000 in the year 2011 (data from conference “Whole Grains on Every Plate” 2012, San Antonio, USA). For bread, breakfast cereals and snacks, the proportion of wholemeal products is around 20% of total, and such figure is increasing. This is true also for products not usually seen in a “wholemeal” version, e.g. pizza and pita breads, cakes and other sweet products, soups, frozen food and baby food. Wholemeal products are not only those based on wheat, since there can be also wholemeal rice and wholemeal corn, and other less common as wholemeal quinoa. Wholemeal flours are not only richer in fibres from bran, but also richer in vitamins and minerals compared to “white” flours, containing almost exclusively starch. From the structural point of view, the Codex Alimentarius defines fibres as polysaccharides composed by 10 or more units, non hydrolyzable by human intestinal enzymes, therefore they are not digested and they don’t bring any calories. However, some of them can be digested by intestinal microorganisms, that can therefore grow and over-number the others: if these are beneficial strains, the fibres are defined “prebiotic” (4). Fibres are also often divided into “soluble” and “insoluble”: the first ones have shorter chains and are sometimes slightly sweet. This distinction is very important from the technological point of view: every fibre is more or less ideal for a certain product’s formulation. The soluble ones can be easily incorporated in any food product, and their presence does not usually alter the characteristics of the product at all (“invisible fibres”): they can be used to texturize creamy/dairy/fruity products, or even added to beverages! On the contrary, insoluble fibres have a more limited range of applications: they are ideal when added to bakery products dough, being able to texturize them and hold moisture within the dough and final product. Some of the most innovative and interesting fibres for the bakery sector (5-6) are the following:
- DESTRINS and CYCLODESTRINS: they are small to medium size soluble polymers, obtained from starch by hydrolysis. They are appreciated for their vast range of possible applications, and also for their beneficial health effects (e.g. less sharp post-meal glycemic peak compared to simple sugars). Cyclodestrins are ring shaped, and can be used to protect delicate substances (e.g. vitamins, antioxidants, omega-3 fatty acids) before adding them to a certain formulation. They can be rendered heat-resistant and pH-resistant if necessary for the production process, and having no colour and no taste they are ideal for any formulation, even beverages.
- PEA FIBRES: they are mainly represented by pectins, ideal to be used in bakery products rendering them soft in the inside and crunchy in the outside. This effect can be used for “critical” applications such us partial substitution of the expensive almond flour for the outer shell crunchiness of macaroons, or for the partial substitution of expensive thickeners as Guar gum. Compared to other insoluble fibres, they can bind higher amounts of water and they disturb less the gluten structure formation. They can also be used to give structure to bakery products fillings, either cream based or fruit based.
- FENUGREEK (Trigonella foenum-gracium) FIBRES: the aromatic and bitter seeds of this plant have been used for centuries in Chinese and Indian traditional medicine, for their antibacterial and anti inflammatory properties. Those seeds also contain high amounts of insoluble fibres (20-25%) and of galattomannanes (20-25%): the latter are soluble hydrocolloid fibres with characteristics similar to Psyllium fibres and Guar gum. They have excellent technological properties plus beneficial healthy effects, among which cholesterolemia and glycemia control. They can be used as jelly agents, thickeners, emulsifiers and stabilizers in various foods such as cereal-based, bakery and dairy.
It is a soluble vitamin essential for DNA synthesis and repair, and for many other important biochemical activities involving rapid cell growth and multiplication, as fetal and infant growth, and red blood cell production. Therefore, a deficiency of folic acid can lead to anemia and poor development in fetus and children. Its supplementation is recommended during pregnancy and early childhood, and many Countries enforced folic acid fortification in a range of products, in particular cereal-based. This practice is so widespread that there are doubts of possible folic acid overexposure (7). However, this substance has got a very high safety profile.
1) Talbott S.M. et al., 2013. β-Glucan supplementation, allergy symptoms, and quality of life in self-described ragweed allergy sufferers. Food Science & Nutrition, 1(1):90-101
2) Auinger A. et al., 2013. Yeast (1,3)-(1,6)-beta-glucan helps to maintain the body’s defence against pathogens: a double-blind, randomized, placebo-controlled, multicentric study in healthy subjects. European Journal of Nutrition, E-pub ahead of print
3) Mikusova L. et al., 2013. Nutritional, antioxidant, and glycaemic characteristics of new functional bread. Journal of Chemical Papers, E-pub ahead of print
4) Roberfroid M. et al., Prebiotic effects: metabolic and health benefits. British Journal of Nutrition, 2010. 104(suppl 2)
5) Ktenioudaki A, and Gallagher E., Recent advances in the development of high-fibre baked products – Review article. Trends in Food Science & Technology, 2012. 28(1)
6) Niba L., Progress in fiber-enriched foods. Food Technology, 2012. 66(11)
7) Fajardo V et al., 2013. Lack of data on Folate in convenience foods: should ready-to-eat products be considered relevant for folate intake? The European challenge. Journal of Food Composition and Analysis. E-pub ahead of print
by Rita Lorenzini