Effect of Antimicrobial Edible Additives on Cassava Starch Biobased Films Characterization

Transcription

1 Effect of Antimicrobial Edible Additives on Cassava Starch Biobased Films Characterization Ana C. L. Attarian; Viviane Kechichian; Pricila Veiga-Santos; Cynthia Ditchfield; Carmen C. Tadini* Food Engineering Laboratory, Chemical Engineering Department, Escola Politécnica, São Paulo University. P.O. Box 61548, , São Paulo, SP, Brazil. *Phone , Fax number e- mail: Written for presentation at the 2006 CIGR Section VI International Symposium on FUTURE OF FOOD ENGINEERING Warsaw, Poland April 2006 Abstract. Antimicrobial films appear in response of the searching for more competitive and aggregated value packaging. With the aim of developing packages that, besides active are also biodegradable, this work proposes to study the effect of antimicrobial additives (honey, cinnamon powder, clove powder, orange essential oil, pepper and coffee powder) on the characterization of cassava starch biobased films. The biofilms were characterized through their mechanical properties (tensile strength and elongation at break percentage), water vapor permeability and total solids content. The film forming solution was prepared with cassava starch, plasticizers (sucrose and inverted sugar) and the antimicrobial additives (honey, cinnamon powder, clove powder, orange essential oil, pepper and coffee powder). A cassava starch film containing only sucrose and inverted sugar served as control. To evaluate the biomaterials characterization, a factorial experimental design (2 7-3 ) with 3 central points was applied and the results were evaluated through ANOVA, considering the pure error. The Pareto analysis was also performed to observe the significant effect (with 95% confidence) of the antimicrobial additives on the material characterization (mechanical and barrier properties) and total solids content. The utilization of different antimicrobial additives has affected (p<0.05) the cassava biobased material characterization. As the film forming solutions were casted in iso-solids conditions, no significant difference were observed on the materials total solids content and thickness. Keywords. Active packaging, biofilm, cassava starch, antimicrobial natural additives.

2 Introduction Packaging is used to extend product shelf life (Vermeiren, Devlieghere, Beest, Kruijf & Debevere, 1999) protecting it mechanically and from chemical and biological contamination (Hotchkiss, 1997). However, in an attempt to satisfy consumers that are becoming ever more demanding, active or intelligent packages have been developed (Rooney, 1995). Besides protecting the product they also interact with it, (Rooney, 1995; Vermeiren et al., 1999), providing extra benefits when compared to conventional packages. There are many types of active packages that have been developed, among these are those that present antimicrobial activity, inhibiting or slowing microbial growth in the packaged product, (Appendini & Hotchkiss, 2002), which are particularly important for the food industry. The active packages that have been developed are mostly produced with conventional petroleum based plastics, generating environmental problems related to their use (Arvanitoyannis & Biliaderis, 1998). As an alternative, there has been increasing interest in biodegradable packages and those obtained from renewable sources, (Lourdin, Coignard, Bizot & Colonna, 1997), such as those films made from biological materials like starch (Guilbert, Gontard & Gossis, 1996 and Krochta & Mulder-Johnston, 1997). Cassava starch flexible films have been successfully developed (Henrique, 2002; Parra, Tadini, Ponce & Lugão, 2004 and Veiga-Santos, 2004), and can thus be investigated as a matrix for antimicrobial additives. Cassava starch is nontoxic and has a low cost, while Brazil is the second largest world producer of cassava (FAO, 2005). Though many materials that present antimicrobial activity have been tested, few studies have used natural and edible compounds. Some natural and edible compounds that have been shown to possess effective antimicrobial activity are those derived from cinnamon (Kim, Park & Park, 2004), coffee (Daglia, Papetti, Dacarro & Gazzani, 1998), honey (Taormina, Niemira & Beuchat, 2001; Mundo, Padilla-Zakour & Worobo, 2004), propolis (Sforcin, Fernandes, Lopes, Bankova& Funari, 1999), orange (Caccion, Guizzardi, Biondi, Renda & Ruberto, 1998) and pepper (Prasad & Seenayya, 2000). The objective of this project was to evaluate the influence of these antimicrobial additives on the mechanical properties, water permeability and total solids content of the biodegradable package. A base formulation containing cassava starch, sucrose and inverted sugar was studied, with the addition of: honey, propolis extract, clove powder, cinnamon powder, orange essential oil, pepper and coffee powder. Films obtained from the basic formulation (cassava starch, sucrose and inverted sugar) were used as control. From these results trends will indicate which of these antimicrobial additives can be employed in the development of a biodegradable active package. Materials and Methods Materials Cassava starch (Cargill Agrícola SA, Brazil), sucrose and inverted sugar (Açúcar Guarani AS, Brazil) were employed to obtain the biodegradable films. The antimicrobial additives used were: honey and propolis extract (MN Própolis, Brazil); clove powder, cinnamon powder and pepper (Fuchs Gewürze do Brasil Ltda, Brazil); orange essential oil (Cargill Agrícola SA, Brazil) and coffee powder (Café do Ponto, Brazil).

3 Sample Preparation The base formulation for the films is a water suspension of cassava starch (5%), sucrose (0.7%) and inverted sugar (1.4%) (Veiga-Santos, 2004). The antimicrobial agents were added to the water used to prepare the base films. The films were prepared according to the casting technique, in which 30 g of film forming suspension were dehydrated on plastic Petri dishes kept at 30 "^"C, under renewable circulated air (Veiga-Santos, 2004). The films were stored (23 C, 75% RH) for at least 4 days prior to testing. Film characterization Film characterization was carried out by evaluation of total solids content, mechanical properties (tensile strength and elongation at break) and water permeability. Total solids content The humidity content of preconditioned samples (75% RH, 23 C) was obtained by drying (105 C) until constant weight (Pouplin, Redl & Gontard, 1999). Mechanical Properties Test filmstrips (8 X 2.5 cm) were cut from preconditioned samples (23 C; 75% RH) and mounted between the grips of the probe A/TGT of the TA.XT2i texturometer (Stable Micro Systems, UK). The tests were conducted according to the ASTM D (2001) method (Veiga-Santos, Oliveira, Cereda, Alves & Scamparini, 2005). Ten specimens were tested for each formulation. Film thickness Average film thicknesses of the preconditioned samples (75% RH, 23 C) were obtained using a flat parallel surface micrometer with 1p.m resolution. Five measurements were taken at three different randomly selected positions. Water vapor permeability The samples were analyzed by employing the ASTM E96-80 (1989) method, modified by Gontard, Guilbert & Cuq (1993). The relative humidity outside the cell was fixed at 100% (pure water), and within the cell, 0% (dry silica). For each analysis four cells were prepared, and weighed daily until a 4% weight gain of the silica was attained (Sarantopóulos, Oliveira, Padula, Coltro, Alves & Garcia, 2002). Two control cells were prepared without the film and conditioned likewise. The weight gain of each cell was measured with time and the water vapor permeability was calculated by equation 1 (Sarantopóulos etal., 2002): Where: w/tis calculated from linear regression of the weight gain over time data, A is the film area, e is the film thickness (in ^un), ps is the vapor saturation pressure (mmhg), RH 1 is the relative humidity inside the chamber and RH 2 is the relative humidity inside the cells.

4 Statistical Analysis An incomplete factorial experimental design (2 7-3 ) with 3 central points was applied to enable perception of the influence of the additives on the mechanical properties and water vapor permeability of the films. Table 1 presents the experimental design and the experiments that were conducted. The levels -1, 0 and 1 for each additive are as follows: clove (0, 0.15%, 0.3%), cinnamon (0, 0.15%, 0.3%), honey (0, 10%, 20%), propolis (0, 0.35%, 0.7%), coffee (0, 2.5%, 5%), pepper (0, 5%, 10%) and orange essential oil (0, 0.1%, 0.2%). A statistical program (Statgraphics version 4.0, Manugistics, Inc., USA) was used to perform the ANOVA and determine the significant effects at a 95% confidence level. Table 1. Experimental Design ¹. Formulations Clove Cinnamon Honey Propolis Coffee Pepper Orange Essential The formulations in bold were the ones that have been tested. Oil

5 Results and Discussion The films formed homogeneous solutions with a subtle spicy aroma. The films dried after approximately 12 to 15 h in the drying chamber. Table 2 shows the results obtained. Table 2. Tensile Strength, Elongation at Break and Water Vapor Permeability for the Different Formulations. Formulations Tensile Strength Elongation at Break Water Vapor Permeability (MPa) ¹ (%) ¹ (gh 2 O.(im/m 2.day.mmHg) c,d 46.4 c a, b d, e, f a b, c e, f 68.9 b b, c b, c 67.4 b a, b c, d 65.9 b b, c b 40.9c a, b f 55.0 b, c a b, c a c a 96.3 a c c, d, e 70.9 b a, b ¹ Same letters in a column indicate that there is no significant difference between points (p>0.05 for the Tukey test). The total solids content varied from 84.7% to 87.6%, which is no significant, due to the fact that the film forming solutions were cast in iso-solids conditions. Thus, the results were not affected by differences in total solids content. There were however, significant differences between some of the formulations for the tensile strength, the elongation at break and water vapor permeability. The tensile strength of the control film (that did not contain any antimicrobial additives) was significantly higher than that of the other films, demonstrating that all the additives decrease the tensile strength of the film to some extent. The results were not conclusive as to which additive or combination of additives had the greatest influence on the tensile strength. The elongation at break of the control film was also high, but in this case two formulations could not be considered to be significantly different from the control. These formulations were 3 (clove, cinnamon and propolis) and 9 (propolis, pepper and orange essential oil). All the other formulations presented lower values with the worst being formulations 2 (clove, cinnamon, honey and coffee), 7 (cinnamon, propolis, coffee and orange essential

6 oil), 8 (honey, coffee, pepper and orange essential oil) and 10 (central point-has all the additives at their intermediate concentration). All the films that contained coffee as an additive (2, 8, 11, 14 and 17) had a poorer result, which indicates that coffee would probably not be a suitable additive for the film. The water vapor permeability of the control film was the lowest obtained. Four other formulations presented water vapor permeabilities that are statistically the same as the control (Formulations: 3-clove, cinnamon and propolis; 4-clove, cinnamon, pepper and orange essential oil; 6-cinnamon, honey, propolis and pepper and 9-propolis, pepper and orange essential oil). All the films that contained coffee as an additive (2, 8,11,14 and 17) presented higher water vapor permeabilities, probably due to the fact that coffee is a coarser powder, and therefore is not incorporated properly by the film, causing a higher permeability at the location of the coffee granules. Conclusions More experiments are needed to determine with greater exactitude which ingredients are influencing the results and if there is interaction between them. The results so far indicate that coffee has a negative influence on the film performance, therefore indicating that it should not be used as an additive. All the formulations tested have worsened film performance, particularly for the tensile strength, so these antimicrobial additives are tending to decrease the mechanical properties and increase water vapor permeability, this is probably because many of them are powders and are not completely incorporated by the film, causing discontinuity within the film. The antimicrobial properties of these films must also be tested, since this is the main purpose of the film. Acknowledgements The authors acknowledge the Brazilian Committee for Postgraduate Courses in Higher Education (CAPES) for the scholarships granted. Thanks to Cargill Agrícola SA, Açúcar Guarani SA, MN Própolis, Fuchs Gewürze do Brasil Ltda and Café do Ponto for the ingredients supplied. Nomenclature A area (m ² ) e film thickness (urn) ps vapor saturation pressure (mmhg) RH relative humidity (%) t time (days) w weight gain of film (g) WV ' water vapor permeability (gh 2 O.nm/m 2.day.mmHg)

7 References Appendini, P. & Hotchkiss, J. H Review of antimicrobial food packaging. Innovative Food Science and Emmerging Technologies 3: Arvanitoyannis, I. & Biliaderis, C. G Physical properties of polyol-plasticized edible films made from sodium caseinate and soluble starch blends. Food Chemistry 62(3): Caccion, D. R. L.; Guizzardi, M.; Biondi, D. M.; Renda, A. & Ruberto, G Relationship between volatile components of citrus fruit essential oils and antimicrobial action on Penicillium digitatum and Penicillium italicum. International Journal of Food Microbiology43(1-2): Daglia, M.; Papetti, A.; Dacarro, C. & Gazzani, G Isolation of an antibacterial component from roasted coffee. Journal of Pharmaceutical and Biomedical Analysis 18(1-2): FAO World Production of Cassava. FAOSTAT. Statistical Databases. Agricultural Data. Food and Agriculture Organization of the United Nations. Available at: Accessed 23 September Gontard, N.; Guilbert, S. & Cuq, J. L Water and glycerol as plasticizers affect mechanical and water vapor barrier properties of an edib le wheat gluten film. Journal of Food Science 58(1): Guilbert, S.; Gontard, N. & Gossis, L. G. M Prolongation of the shelf-life of perishable food products using biodegradable films amd coatings. Food Science & Technology - Lebesmittel Wissenschaft & Technologie 29(1,2): Henrique, C. M Caracterização de filmes de féculas modificadas de mandioca como subsídios para a aplicação em pós-colheita de hortículas. PhD Thesis. Botucatu, São Paulo, Brazil: Universidade Estadual Paulista, Faculdade de Ciências Agronômicas. Hotchkiss, J. H Food-packaging interactions influencing quality and safety. Food Additives and contaminants 14( 6,7), Kim, H. -O.; Park, S. -W. & Park, H. -D Inactivation of Escherichia colio157:h7 by cinnamic aldehyde purified from Cinnamomum cassia shoot. Food Microbiology. 21(1): Krochta, J. M. & Mulder-Johnston, C. de Edible and biodegradable polymer films: Challenges and opportunities. Food Technology 51(2): Lourdin, D.; Coignard, L.; Bizot, H. & Colonna, P Influence of equilibrium relative humidity and plasticizer concentration on the water content and glass transition of starch materials. Polymers 38(21): Mundo, M. A.; Padilla-Zakour, O. I. & Worobo, R. W Growth inhibition of foodborne pathogens and food spoilage organisms by select raw honeys. International Journal of Food Microbiology Article in Press. Parra, D. F.; Tadini, C. C.; Ponce, P. & Lugão, A. B Mechanical properties and water vapor transmission in some blends of cassava starch edible films. Carbohydrate Polymers 58: Pouplin, M.; Redl, A. & Gontard, N Glass transition of wheat gluten plasticized with water, glycerol, or sorbitol. Journal of Agricultural and Food Chemistry 47(2):

8 Prasad, M. M. & Seenayya, G Effect of spices on the growth of red halophilic cocci isolated from salt cured fish and solar salt. Food Research International 33(9): Rooney, M. L Overview of active food packaging. In Active Food Packaging, pp London, UK: Blackie Academic & Professional. Sarantopóulos, C. I. G. L.; Oliveira, L. M.; Padula, M.; Coltro, L.; Alves, R. M. V. & Garcia, E. E. C Propriedades de Barreira. In Embalagens Plásticas Flexíveis. Principais Polímeros e Avaliação de Propriedades, pp Campinas, São Paulo, Brazil: Institute of Food Technology, CETEA/ITAL, BR. Sforcin, J. M.; Fernandes, A. JR; Lopes, C. A. M.; Bankova; V. & Funari, S. R. C Seasonal effect on Brazilian propolis antibacterial activity. Journal of Ethnopharmacology 73(1,2): Taormina, P. J.; Niemira, B. A. & Beuchat, L. R Inhibitory activity of honey against foodborne pathogens as influenced by the presence of hydrogen peroxide and level of antioxidant power. International Journal of Food Microbiology 69(3): Veiga-Santos, P Elaboração, aditivação e caracterização de biofilmes à base de fécula de mandioca. PhD Thesis. Campinas, São Paulo, Brazil: Universidade Estadual de Campinas, Faculdade de engenharia de Alimentos. Veiga-Santos, P., Oliveira, L. M.; Cereda, M. P., Alves, A. J. & Scamparini, A. R. P Mechanical properties, hydrophilicity and water activity of starch-gum films: Effect of additives and deacetylated xanthan gum. Food Hydrocolloids 19: Vermeiren, L.; Devlieghere, F.; Beest, M. van; Kruijf, N. de & Debevere, J Developments in the active packaging of foods. Trends in Food Science & Technology10: