Elsevier

Food and Bioproducts Processing

Volume 123, September 2020, Pages 354-366
Food and Bioproducts Processing

Techno-economic analysis for probiotics preparation production using optimized corn flour medium and spray-drying protective blends

https://doi.org/10.1016/j.fbp.2020.07.002Get rights and content

Highlights

  • Optimized spray-drying protectant blend increases cell’s survival rate over 4-fold.

  • Techno-economic analysis of the model process indicated high NPV value.

  • Inulin cost was indicated a highly sensitive parameter for unit production cost.

  • Costly unit operation — separation and washing of probiotic cells was excluded.

  • Market price of synbiotic preparation was estimated to be $5.00 per kg.

Abstract

Current production of probiotic preparations must meet several criteria to be competitive on the market, like inexpensive growth medium based on sustainable resources, reduction of the number of unit operations, and exploitation of cost-effective preservation method. Implementation of the new solutions should not negatively affect the quality of the product, such as the number of living cells or the product safety. In the present study, we used a highly concentrated, raw corn flour-based (CF) medium for cultivation of probiotic L. plantarum LOCK 0860 strain and as a matrix in the following spray-drying process. Prior to drying, the post-culturing liquid was supplemented with a newly developed, optimized blend of protective agents, shown to increase the cell’s viability over 4-fold. Experimentally obtained data were used for the process model simulation at industrial scale, where the optimized probiotic component was supplemented with inulin as the prebiotic and standardization agent. Techno-economic analysis of this process model indicated a high net present value (NPV) at a selling price of $5.00 per kg of the preparation, which represent highly promising economic benefits. Sensitivity of unit production cost and the number of batches per year was estimated in the simulation, and the critical factors were identified, as well.

Introduction

Probiotics, as defined by Food and Agriculture Organization of the United Nations (FAO) and World Health Organization (WHO), are “live micro-organisms which when administered in adequate amounts confer a health benefit on the host” (FAO/WHO, 2001). New probiotics formulations and functional foods are the major driving factors for continuous growth in the food and feed sector. It has been estimated that the total market value of both human and animal probiotics will gain revenues of 52 (2020) and 4.71 billion dollars (2021), respectively (Zoumpopoulou et al., 2018). Amongst different strains used as the probiotics, those belonging to Lactobacillus and Bifidobacterium genera have gained the greatest importance (Vinderola et al., 2017). While many technologies of the probiotics production are well established on the market, research in this field is further continued. Recent scientific efforts have been focused on characterization of probiotic properties of new strains, and formulation of the final products as solid and dehydrated preparations, which assure stability during long-term storage. Newly obtained Lactobacillus plantarum strains are considered particularly suitable for the production of desiccated probiotics (Bustamante et al., 2017; Kalita et al., 2018).

To meet the demands of the growing food and feed sector, innovative production solutions are required. Highly-efficient and cost-effective methods for the probiotic bacteria preservation are currently intensively sought (Tan et al., 2018). Spray-drying, being the most high-throughput and high-capacity unit operation of converting liquid probiotics into a solid and dehydrated form, is gaining significant attention. High capacity of this process, reaching over 20 tons of powder per hour, is highly desired in the probiotics production (Fu et al., 2018). Nevertheless, in the last few years, freeze-drying was the preferred method of the probiotics preservation, especially for non-thermotolerant strains, due to milder process conditions than in the case of spray-drying. Indeed, lower processing temperature can positively affect the number of living cell counts in the final preparation. However, freeze-drying is more expensive due to high specific energy consumption and much lower capacity of this process, when compared to spray-drying (Huang et al., 2017b). On the other hand, viability of the microbial cells during spray-drying can be increased by a number of different strategies, making this process highly competitive and attractive (Golowczyc et al., 2010). It has been evidenced, that the main reasons for inactivation of the microbial cells during spray-drying are dehydration (causing osmotic stress) and high temperature (Perdana et al., 2013). In contrast to the other groups of microorganisms, lactic acid bacteria (LAB) are not capable to synthesize osmo-protecting compounds that minimize the harmful effects of dehydration. Thus, adding specific protectants, either during growth of LAB or directly prior to the spray-drying process, is recommended to compensate the difference in the osmotic pressure between the cell interior and the environment (Morgan et al., 2006). The composition of the applied protectants, together with the drying conditions (the inlet and especially, the outlet temperature) are the key factors affecting bacterial cells viability during spray-drying. The other factors impacting the cells survival during the drying process are: the phase of bacterial growth, pre-heating adaptation and, above all, characteristics of the strain (Fu and Chen, 2011).

In order to reduce the overall the probiotics production costs, cultivation of the probiotic bacteria can be carried out using renewable sources of carbon and nitrogen, such as wastes from the food industry, animal-free agro-residues, and starchy crops or wastes (Coghetto et al., 2016; Hofvendahl and Hahn-Hägerdal, 2000). Flour-rich waste streams and by-products from bakery, confectionery and wheat milling plants were indicated as sustainable streams of raw materials for microbial media formulations to be used in large scale production (Tsakona et al., 2014). Corn is the third most cultivated cereal, but only 5% of the corn grain, either cooked or processed into flour, are directly consumed by human. The remaining 95% of the corn grain is transformed into fodder or ethanol (Yang et al., 2017). It was suggested that it is crucial to find further ways to improve the applicability of corn (Yang et al., 2017). Corn flour hydrolysate was successfully used as an economical substrate for the production of simple organic compounds, such as ethanol and d-lactic acid (Szymanowska-Powałowska et al., 2014; Zhao et al., 2014). Using starchy crops or wastes is one of the solutions which may contribute to lowering the cost of nutrients, necessary for the probiotics bacteria growth. On the other hand, exploitation of starchy substrates for some of the probiotic strains may be problematic, due to the lack of appropriate enzymatic machinery decomposing starch, which consequently necessitates the addition of hydrolysing enzymes to secure the supply of simple carbohydrates for microbial growth (Mazzoli et al., 2014). On the other hand, some of the LABs, like L. plantarum, are known for their efficient amylolytic activity (Zielińska et al., 2000). Furthermore, limited ability of LAB to synthesize B-vitamins and amino-acids, makes the bacteria able to grow only in complete, rich media. For this reason, starch-based media require supplementation with complex nutrients that increases the overall costs (Hofvendahl and Hahn-Hägerdal, 2000). Nevertheless, in spite of applying these pre-treatments, such starch-based production still remains profitable at industrial scale, when compared to the production based on synthetic media.

Another aspect in the production of probiotic preparations is the possibility of combining them with prebiotics. Prebiotic is defined as a substrate that is selectively utilised by host microorganisms conferring a health benefit (Gibson et al., 2017). Inulin, fructo-oligosaccharides (FOS) and galactooligosaccharides (GOS) are the most commonly used prebiotic agents (Pineiro et al., 2008). The combination of the prebiotic and the probiotic is termed a synbiotic. The synbiotics are known to confer a synergistic health benefit, which results from specific stimulation of the probiotic component by the prebiotic agent (de Vrese and Schrezenmeir, 2008). This mechanism does not rely only on improving the cells survival during transit through gastrointestinal tract, but also on stimulating their growth in the intestine (Pandey et al., 2015).

The ultimate aim of this study was to optimize a process of probiotics production by adopting a multidirectional strategy. Exploitation of an inexpensive substrate for the probiotic strain growth, a reduced number of unit operations, and optimization of the spray-drying procedure, were all implemented in this strategy. Inexpensive, starch-based medium was double used for the strain growth and for the preservation of the probiotics during spray-drying, which allowed to reduce the number of unit operations. The drying procedure was preceded by the addition of an optimized blend of protectants. Experimental data, were further used to conduct simulation of a synbiotic preparation production at industrial scale. The simulated synbiotic was composed of the here developed probiotic preparation and inulin, used as the prebiotic and standardization agent. Techno-economic evaluation of the process model and sensitivity analysis of the key parameters was conducted.

Section snippets

Microorganism

Lactobacillus plantarum LOCK 0860 was used in this study as the model probiotic strain. The strain was obtained from Lodz University of Technology as cryobank beads (Mast Diagnostica, Germany) and stored at −20 °C. Its probiotic properties were previously documented (Śliżewska et al., 2012).

Phenotype MicroArrays tests

Phenotype MicroArrays (PMs) tests were conducted using Biolog technology (Biolog, USA) and PM1-2 plates. The PM1-2 are separate sets of 96 C-source substrates. L. plantarum LOCK 0860 was grown overnight at

Phenotype profiling of L. plantarum LOCK 0860 - C-source utilization profile

Cell-based phenotypic testing technologies, as the here used Phenotype MicroArrays, greatly assist medium optimization efforts and allow to gain deeper understanding of a given microorganism performances in a specific growth medium (Greetham, 2014). Here conducted phenotype profiling, evidenced that L. plantarum LOCK 0860 is able to assimilate the following C-sources: l-arabinose, N-acetyl-d-glucosamine, d-galactose, d-trehalose, d-mannose, d-gluconic acid, d-xylose, d-mannitol, d-ribose, d

Conclusions

The competitive production processes of stable probiotics and synbiotics preparations is currently an urgent need of the food and feed industry. Amongst different strategies of increasing the market attractiveness of a particular process, development of inexpensive, sustainable growth medium, reduction of the number of unit operations, and exploitation of cost-effective preservation method, are the most promising. All these issues were addressed in the present study.

In the current research we

Declaration of interests

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Declaration of Competing Interest

The authors report no declarations of interest.

Acknowledgements

This study was financially supported by the National Centre for Research and Development (NCBR) under the project PBS3/A8/32/2015.

References (52)

  • D. Kalita et al.

    Characteristics of synbiotic spray dried powder of litchi juice with Lactobacillus plantarum and different carrier materials

    LWT Food Sci. Technol.

    (2018)
  • S. Khem et al.

    The behaviour of whey protein isolate in protecting Lactobacillus plantarum

    Food Chem.

    (2016)
  • P. Liu et al.

    Glass transition temperature of starch studied by a high-speed DSC

    Carbohydr. Polym.

    (2009)
  • G.M. Maciel et al.

    Microencapsulation of Lactobacillus acidophilus La-5 by spray-drying using sweet whey and skim milk as encapsulating materials

    J. Dairy Sci.

    (2014)
  • M.J. Martín et al.

    Microencapsulation of bacteria: a review of different technologies and their impact on the probiotic effects

    Innov. Food Sci. Emerg. Technol.

    (2015)
  • R. Mazzoli et al.

    Towards lactic acid bacteria-based biorefineries

    Biotechnol. Adv.

    (2014)
  • C.A. Morgan et al.

    Preservation of micro-organisms by drying; a review

    J. Microbiol. Methods

    (2006)
  • J. Perdana et al.

    Dehydration and thermal inactivation of Lactobacillus plantarum WCFS1: comparing single droplet drying to spray and freeze drying

    Food Res. Int.

    (2013)
  • R. Rajam et al.

    Microencapsulation of Lactobacillus plantarum (MTCC 5422) with fructooligosaccharide as wall material by spray drying

    LWT Food Sci. Technol.

    (2015)
  • S. Siragusa et al.

    Fermentation and proteome profiles of Lactobacillus plantarum strains during growth under food-like conditions

    J. Proteomics

    (2014)
  • E.O. Sunny-Roberts et al.

    The protective effect of monosodium glutamate on survival of Lactobacillus rhamnosus GG and Lactobacillus rhamnosus E-97800 (E800) strains during spray-drying and storage in trehalose-containing powders

    Int. Dairy J.

    (2009)
  • D. Szymanowska-Powałowska et al.

    Stability of the process of simultaneous saccharification and fermentation of corn flour. The effect of structural changes of starch by stillage recycling and scaling up of the process

    Fuel.

    (2014)
  • S. Tsakona et al.

    Formulation of fermentation media from flour-rich waste streams for microbial lipid production by Lipomyces starkeyi

    J. Biotechnol.

    (2014)
  • G. Vinderola et al.

    Probiotics in nondairy products

  • R. Wijayasinghe et al.

    Water-lactose behavior as a function of concentration and presence of lactic acid in lactose model systems

    J. Dairy Sci.

    (2015)
  • K.J. Zielińska et al.

    Degradation of raw potato starch by an amylolytic strain of Lactobacillus plantarum C

    Prog. Biotechnol.

    (2000)
  • Cited by (14)

    • Effect of sub-lethal heat stress on viability of Lacticaseibacillus casei N in spray-dried powders

      2022, LWT
      Citation Excerpt :

      Gum acacia (GA) is a natural composite of proteins and polysaccharides with properties like excellent emulsification and high solubility (Gul & Atalar, 2019). The use of corn-starch as an encapsulating ingredient in probiotic microencapsulation has solved a number of technological challenges, including thermal stability, controlled release of bioactive molecules, and longer shelf life (Archacka, Celińska, & Białas, 2020). The primary objective of this study was to evaluate the effect of different encapsulating agents on L. casei (N) survival during spray drying and to investigate the influence of sub-lethal heat stress on the survivability of Lacticaseibacillus casei N (N) during spray drying and its storage at 4 °C for 90 days.

    • Probiotic bacteria stabilized in orally dissolving nanofibers prepared by high-speed electrospinning

      2021, Food and Bioproducts Processing
      Citation Excerpt :

      Therefore, the effect of various excipients (glucose, lactose, mannitol, saccharose, trehalose, inulin, and skim milk) was investigated in this study using a PVA-PEO-based formulation containing L. paracasei. Inulin (Avila-reyes et al., 2014), skim milk (Fávaro-Trindade and Grosso, 2002), glucose (Strasser et al., 2009), lactose (Higl et al., 2007), mannitol (Savini et al., 2010), saccharose (Tan et al., 2020) and trehalose (Archacka et al., 2020) were used successfully during freeze-drying and spray-drying, thus they are potentially able to increase the survival of the bacteria during electrospinning. Besides maintaining a high count of viable cells in the formulations, the mass production of nanofibers is necessary for the industrial use of electrospinning technology.

    • Plant-based milk substitutes as emerging probiotic carriers

      2021, Current Opinion in Food Science
      Citation Excerpt :

      These results suggest that packaging material may also have a strain-dependent effect on probiotic viability [48]. Certain probiotic carrier approaches such as microencapsulation [49••] and spray drying [50,51••] have been suggested as effective strategies to improve probiotic viability during fermentation and storage. Whereas, fermentation process contributed significantly to achieve increased survivability of probiotics in both coconut-milks and hemp-milks [34].

    • Advancement in the research and development of synbiotic products

      2023, Microbial Bioreactors for Industrial Molecules
    View all citing articles on Scopus
    View full text