Wholemeal and semi-wholemeal flour: milling technique and biological value

While the wholemeal flour offers the maximum integrity of the cereal – keeping intact the content of dietary fibers, micronutrients, and bioactive compounds – the semi-wholemeal flours arise as a valuable technological compromise. The ‘type 2’ and ‘type 1’ flours allow benefiting from an appreciable amount of micronutrients, while ensuring versatility and sensory acceptance.

Milling and sifting

In the Italian milling system, the classification of flours is not based on ‘refining’, since no chemical process exists, but rather on  degree of sifting (DPR 187/01). Sifting is the milling process that, through successive sieving, allows modulating the presence of the peripheral parts of the grain (bran e germ) in the flour, after milling. Thus, the following are distinguished:

• wholemeal flourobtained without removing the bran fractions and the germ. The sifting is minimal and the entire grain contributes to the final composition;

• type 2 flourcharacterized by intermediate sifting, with a significant presence of the peripheral parts of the grain, while maintaining good technological performance;

• type 1 floursubjected to a more selective sifting compared to type 2, but still preserving a significant amount of fibers and micronutrients compared to more sifted flours (e.g., type 00).

This modulation allows Italian mills to offer flours with differentiated nutritional and sensory profiles, adaptable to various professional applications.

Nutritional profile of wholemeal and semi-wholemeal flour

Dietary fibers

The  Dietary fibers, concentrated in the bran parts of the grain, represent one of the main strengths of flours with low sifting degree. According to CREA data, whole wheat flour contains on average 8.4 g of total fiber per 100 g – compared to 2.2 g of type 00 – with an optimal ratio between insoluble fibers (cellulose and hemicellulose) and  soluble fibers (beta-glucans and arabinoxylans). These fibers:

• modulate carbohydrate absorption, with positive effects on postprandial glycemic response;

• contribute to  satiety through gastric distension and slowing of gastric emptying;

• promote balance in  gut microbiota, supporting the production of short-chain fatty acids (SCFA) with systemic metabolic effects (Reynolds et al., 2020).

Type 2 and type 1 flours in turn offer a balanced compromise between fiber content, technological performance, and organoleptic properties of derived products.

Vitamins and minerals

Maintaining the peripheral fractions of the wheat grain allows a greater availability of:

• B group vitamins (thiamine, riboflavin, niacin, folates), involved in energy metabolism, with concentrations up to 5 times higher than type 00 flour;

• vitamin E (tocopherols and tocotrienols), with antioxidant and protective function of cell membranes;

• minerals such as  phosphorus, potassium, iron, magnesium, zinc, selenium, essential for numerous physiological processes, including immune function and protein synthesis.

The bioavailability of these micronutrients can be optimized through techniques of  prolonged leavening and sourdough fermentation, so-called 'mother dough' or 'sourdough starter' (Verni et al., 2021).

Bioactive compounds

Less refined flours retain a significant amount of  phenolic compounds (ferulic, syringic, vanillic acids),  lignans and other  phytocompounds naturally present in the grain, with concentrations up to 10 times higher in wholemeal flours compared to more refined flours (type 00). These compounds are associated with protective effects against  oxidative stress and low-grade chronic inflammation (Martini et al., 2015).

Health benefits

The regular use of wholemeal and semi-wholemeal flour in the diet is associated with several favorable effects, documented by recent epidemiological evidence and intervention studies. It is useful to specify that such evidence has not yet been evaluated by the European Food Safety Authority, as no operator has so far submitted a request for authorization of the related health claims pursuant to Regulation (EC) No 1924/06.

Glycemic control and prevention of type 2 diabetes

Thanks to the presence of fiber and the more complex structure of the food matrix, products obtained with wholemeal and semi-wholemeal flour promote slower starch digestion, contributing to a  more gradual glycemic response and a lower postprandial insulin peak. A recent meta-analysis that examined 10 population studies and 37 controlled clinical trials highlighted that the consumption of three daily servings of whole grains (about 50 g/day of whole ingredients) is associated with a 24% reduction in the risk of developing type 2 diabetes, with a dose-response relationship indicating increasing benefits with higher consumption (Ying et al., 2024).

Cardiovascular health

Dietary fibers, particularly soluble ones, participate in the regulation of the lipid profile, supporting the reduction of LDL cholesterol through the sequestration of bile acids and the modulation of hepatic synthesis. Prospective studies show that each serving daily of whole grains is associated with a 6-9% reduction in the risk of major cardiovascular events and cardiovascular mortality (Reynolds et al., 2020). Phenolic compounds also contribute to endothelial protection and modulation of blood pressure.

Gut microbiota and metabolic health

Fibrous components serve as a fermentable substrate for the gut microbiota, favoring the proliferation of beneficial bacterial species (Bifidobacterium, Lactobacillus, Faecalibacterium prausnitzii) and the production of  short-chain fatty acids (butyrate, propionate, acetate). These metabolites exert systemic effects on metabolic regulation, intestinal barrier integrity, and immune function (Vanegas et al., 2017).

A randomized controlled study documented that replacing refined cereals with whole grains for 6 weeks results in improvements in insulin sensitivity and  reduction of systemic inflammatory markers (such as C-reactive protein and interleukin-6) in adult individuals (Vanegas et al., 2017). Another trial showed that whole grains increase glucose-stimulated insulin secretion and pancreatic beta-cell function independently of weight loss (Kirwan et al., 2019).

Body weight control

The greater satiety power and lower energy density of whole grain products promote  Body weight control. A recent meta-analysis highlights that regular consumption of whole grains is associated with less long-term weight gain and a reduced risk of abdominal obesity (Della Pepa et al., 2018).

Cancer prevention

Epidemiological evidence suggests that whole grain consumption may be associated with a reduced risk of colorectal carcinoma (17% reduction for every 90 g/day of whole grains) and other digestive system tumors, through mechanisms including modulation of intestinal transit, production of short-chain fatty acids (SCFA), and the antioxidant action of phenolic compounds (Reynolds et al., 2020).

Technological and sensory value

From an application point of view, type 1 and type 2 flour is increasingly appreciated for:

• more complex and characteristic aromas, derived from Maillard reactions and the presence of volatile compounds in the germ and bran;

• greater  structure e personality in baked goods, with more rustic and authentic organoleptic notes;

• suitability for the production of  breads, pizzas e pastry products with an improved nutritional profile and high sensory acceptability when properly processed.

Controlled milling allows to combine sensory quality, nutritional value, and processability. Prolonged leavening and fermentation techniques improve the digestibility and structure of the doughs (Verni et al., 2021).

Conclusions

Italian wholemeal and semi-wholemeal flour (type 1 and type 2) best expresses Italian milling expertise, based on precise milling control and on enhancing the wheat grain. Rich in fiber, micronutrients, and bioactive compounds, these flours represent a strategic choice to develop  functional foods authentic and distinctive, in line with the expectations of an increasingly market oriented towards  nutritional qualityto  sustainability and technological transparency. The most recent scientific evidence confirms the protective role of whole grains in preventing major chronic non-communicable diseases, strengthening the positioning of these flours within the Mediterranean diet context and public health strategies.

Dario Dongo

Credit cover: Molino Moras Srl Benefit Company 

Bibliography

• CREA – Council for Agricultural Research and Economics. (2023).  Food composition tables. Whole wheat flour. CREA Food and Nutrition. https://www.alimentinutrizione.it/tabelle-nutrizionali/000240

• CREA – Council for Agricultural Research and Economics. (2023).  Food composition tables. Wheat flour, Type 00. CREA Food and Nutrition. https://www.alimentinutrizione.it/tabelle-nutrizionali/000220

• Della Pepa, G., Vetrani, C., Vitale, M., & Riccardi, G. (2018). Wholegrain Intake and Risk of Type 2 Diabetes: Evidence from Epidemiological and Intervention Studies.  Nutrients, 10(9), 1288. https://doi.org/10.3390/nu10091288

• Presidential Decree of February 9, 2001, no. 187. Regulation for the revision of regulations on the production and marketing of flour and pasta products, pursuant to Article 50 of Law February 22, 1994, no. 146.  Official Gazette of the Italian Republic. https://www.normattiva.it/uri-res/N2Ls?urn:nir:presidente.repubblica:decreto:2001;187

• Kirwan, J. P., Malin, S. K., Scelsi, A. R., Kullman, E. L., Navaneethan, S. D., Pagadala, M. R., Haus, J. M., Filion, J., Godin, J. P., Kochhar, S., & Ross, A. B. (2019). A whole-grain diet reduces cardiovascular risk factors in overweight and obese adults: A randomized controlled trial.  The Journal of Nutrition, 146(11), 2244–2251.  https://doi.org/10.3945/jn.116.230508

• Kristensen, M., Toubro, S., Jensen, M. G., Ross, A. B., Riboldi, G., Petronio, M., Bügel, S., Tetens, I., & Astrup, A. (2012). Whole grain compared with refined wheat decreases the percentage of body fat following a 12-week, energy-restricted dietary intervention in postmenopausal women.  The Journal of Nutrition, 142(4), 710–716.  https://doi.org/10.3945/jn.111.142315

• Martini, D., Taddei, F., Ciccoritti, R., Pasquini, M., Nicoletti, I., Corradini, D., & D’Egidio, M. G. (2015). Variation of total antioxidant activity and of phenolic acid, total phenolics and yellow coloured pigments in durum wheat (Triticum turgidum L. var.  durum) as a function of genotype, crop year and growing area.  Journal of Cereal Science, 98, 103172. https://doi.org/10.1016/j.jcs.2015.06.012

• Reynolds, A. N., Akerman, A. P., & Mann, J. (2020). Dietary fibre and whole grains in diabetes management: Systematic review and meta-analyses.  PLoS Medicine, 17(3), e1003053.  https://doi.org/10.1371/journal.pmed.1003053

• Vanegas, S. M., Meydani, M., Barnett, J. B., Goldin, B., Kane, A., Rasmussen, H., Brown, C., Vangay, P., Knights, D., Jonnalagadda, S., Koecher, K., Karl, J. P., Thomas, M., Dolnikowski, G., Li, L., Saltzman, E., Wu, D., & Meydani, S. N. (2017). Substituting whole grains for refined grains in a 6-wk randomized trial has a modest effect on gut microbiota and immune and inflammatory markers of healthy adults.  The American journal of clinical nutrition, 105(3), 635–650. https://doi.org/10.3945/ajcn.116.146928

• Verni, M., Dallinger, M., Schalow, M., & Arendt, E. K. (2021). Sourdough fermentation as a tool to improve the nutritional and health-promoting properties of its derived-products. Fermentation, 7(4), 246. https://doi.org/10.3390/fermentation7040246

• Ying, T., Zheng, J., Kan, J., Li, W., Xue, K., Du, J., Liu, Y., & He, G. (2024). Effects of whole grains on glycemic control: A systematic review and dose-response meta-analysis of prospective cohort studies and randomized controlled trials.  Nutrition Journal, 23(1), 47.  https://doi.org/10.1186/s12937-024-00952-2