Probiotic edible films as a new strategy for developing functional bakery products: The case of pan bread

Abstract

In the present paper, a novel approach for the development of probiotic baked cereal products is presented. Probiotic pan bread constructed by the application of film forming solutions based either on individual hydrogels e.g. 1% w/w sodium alginate (ALG) or binary blends of 0.5% w/w sodium alginate and 2% whey protein concentrate (ALG/WPC) containing Lactobacillus rhamnosus GG, followed by an air drying step at 60 °C for 10 min or 180 °C for min were produced. No visual differences between the bread crust surface of control and probiotic bread were observed. Microstructural analysis of bread crust revealed the formation of thicker films in the case of ALG/WPC. The presence of WPC improved significantly the viability of L. rhamnosus GG throughout air drying and room temperature storage. During storage there was a significant reduction in L. rhamnosus GG viability during the first 24 h, viable count losses were low during the subsequent 2–3 days of storage and growth was observed upon the last days of storage (day 4–7). The use of film forming solutions based exclusive on sodium alginate improved the viability of L. rhamnosus GG under simulated gastro-intestinal conditions, and there was no impact of the bread crust matrix on inactivation rates. The presence of the probiotic edible films did not modify cause major shifts in the mechanistic pathway of bread staling – as shown by physicochemical, thermal, texture and headspace analysis. Based on our calculations, an individual 30–40 g bread slice can deliver approx. 7.57–8.98 and 6.55–6.91 log cfu/portion before and after in-vitro digestion, meeting the WHO recommended required viable cell counts for probiotic bacteria to be delivered to the human host.

Stability of Lactobacillus rhamnosus GG incorporated in edible films: Impact of anionic biopolymers and whey protein concentrate

“…1), which is in agreement with the findings from our previous studies (Soukoulis et al., 2014, Soukoulis et al., 2014c, Soukoulis et al., 2016). As a general trend, polysaccharide based films (PEC, LSA, HSA and κ-CAR/LBG) exerted the highest cell lethality (96.2–99.9%, please note that numbers in Fig.…”

“…In a previous work, we demonstrated that the inclusion of L. rhamnosus GG in edible films, comprising whey protein concentrate and sodium alginate, assisted bacterial cells to withstand heat and osmotic stress upon bread production and storage whereas it also enhanced their survival throughout ingestion and gastrointestinal passage (Soukoulis et al., 2014). In the present work, we aim to further investigate the technological feasibility of edible films comprising selected biopolymers with established good film forming properties (namely low esterified amidated pectin (PEC), low (LSA) and high (HSA) viscosity sodium alginate, porcine skin gelatine (GEL) and kappa-carrageenan/locust bean gum (κ-CAR/LBG)), in the presence or absence of whey protein concentrate (WPC) as potential vehicles for L. rhamnosus GG.…”

Whey-derived valuable products obtained by microbial fermentation

“…Bread Soukoulis et al (2014) formulated a probiotic bread by applying a film-forming solution (edible film) based on a binary blend containing 0.5 % (w/v) sodium alginate and 2 % (w/v) WPC inoculated with the probiotic strain Lactobacillus rhamnosus GG. Edible films are thin layers of biopolymers that can be consumed and are usually applied on the food surface by spraying or brushing.…”

Trends in dairy and non-dairy probiotic products - a review

“…rhamnosus GG and the viability was found to be 6.55-6.91 log cfu/30-40 g portion of bread after in vitro digestion under simulated gastro-intestinal conditions and no impact of the bread crust matrix on cell inactivation was noticed (Soukoulis et al 2014). Meat mainly in the form of sausages is also being used as an alternate to dairy based probiotic foods.…”