INTRODUCTION

The spread of non-communicable diseases (NCD) is considered one of the top health problems worldwide. A low intake of fruits and vegetables in conjunction with a high consumption of foods rich in saturated and trans fats, salt and sugar has been reported to be the main cause of a considerable proportion of deaths associated to NCDs [1,2]. NCD Global Action Plan 2013–2020 proposes, among other objectives, to reduce the impact of diabetes, giving priority to actions to prevent overweight and obesity [3]. For this reason, interventions aiming at encouraging people to engage in healthier eating habits have been identified as one of the top priorities for reducing the burden of NCD [4]. To assist in the achievement of these objectives, an alternative for roasted chicken skin was proposed in the research carried out [5]. In this work, a heat treated calcium alginate dry film prepared with chicken stock was developed. This film presented similar characteristics to roasted chicken skin when it was heated. Heat treatment of the dry film for 15 min at 130°C produced the development of an opaque maroon color and an increased in their brittleness. This information can be used by product developers, culinary scientists and professional chefs in designing food products in which these kinds of films are employed to wrap or cover the top of chicken meat pieces that are then subjected to cooking. These studies suggest a potential use of heat treated-chicken stock films as a substitute of roasted chicken skin since the crisp texture and optical properties were alike. This is the basis for the preparation of healthier alternatives to the traditional roasted skin through reduction unhealthy components, such as fat (including cholesterol) and carcinogenic compounds, without loss of overall flavor intensity [5]. However, sensory studies are needed before the product can be recommended.

Chicken stock was prepared using 2kg of roasted chicken carcass and a mirepoix consisting of 250g of onion, 150g of carrot, 150g of celery and 150g of leek. All the ingredients were placed in a stock pot and covered with cold water. The mixture was brought to the boil and then, 1g of thyme, 1g of rosemary, 1g of parsley, and 0.8g of black peppercorn were added. After simmered very gently for 6h, the chicken stock was filtered and clarified using egg white. Finally chicken stock was filtered again, aliquoted and stored at –20°C [5]. The preparation of dry films was made according to Báez et al. [5]. Solid SA was gently added to chicken stock in order to give a final SA concentration of 0.9 percent (w/v). The mixture was stirred for 12 h until homogeneity was obtained. After that, the solution was heated at 60°C, degassed and 88g of it were poured into square plastic Petri dishes of 12cm side. The plates were left to rest at 25°C for 3 h and then introduced into an oven for 3h at 50°C. The dry films were withdrawn from Petri dishes and stored in plastic containers. These dry films were named Alg-St. Films with physical defects such as air bubbles, holes, and cracks were discarded. The selected films were stored at 25°C and 55 percent RH for 24h until testing. Samples chicken breast (20 mm x 20 mm x 30 mm) covered with natural skin or Alg-St were cooked at 180°C for 18 minutes and served warm (40 °C) to panelists. Water was provided for oral rinsing between the samples.

Sensory evaluation of the new product was carried for various attributes namely color, shine, thickness, appearance, aroma, flavor, foreign flavor, crispness, chewiness, adhesiveness and overall palatability. The sensory profile of both samples was determined according to the quantitative descriptive analysis methodology (QDA) proposed by Stone et al. [6]. A trained panel of nine members evaluated the samples for all the previously determined attributes (color, shine, thickness, appearance, aroma, flavor, foreign flavor, crispness, chewiness, adhesiveness and overall palatability), using an unstructured scale of 10- point being scored from 1 (least favorable) to 10 (most favorable). Panelists were seated in a room free of noise and odors and suitably illuminated. Data were presented as the arithmetic mean ± SEM (Standard Error of the Mean). The results of the QDA were analyzed using analysis of variance (ANOVA), followed by Tukey’s honestly significant difference (HSD) test. Significance was accepted at p < 0.05.

Figure 1 shows a photograph of both cooked samples. Results of the sensory evaluation are presented in Table 1. No significant differences between the chicken skin and the film were observed in color, appearance, aroma, flavor, foreign flavor, crispness, chewiness and adhesiveness (Table 1 and Figure 2). These similarities would allow the acceptability of the developed product. Moreover, the overall palatability attribute of the film sample obtained the higher score, that is to say, the better sensory evaluation. A significant difference was observed in the shine of the samples. There was also a significant difference in the thickness of natural skin due to the presence of fat in its structure. It could be possible to increase the thickness of Alg-St by using greater volumes of the casting solution.

CONCLUSION

In conclusion, sensorial characteristics of both cooked products were no different, except in thickness and shine. Moreover, the film presented the higher overall palatability score. These facts make it possible to replace high-fat chicken skin with Alg-St.

1.       World Health Organization (2009) Global health risks. Mortality and burden of disease attributable to selected major risks. WHO, Geneva, Switzerland.

2.       World Health Organization (2011) Global status report on non-communicable diseases 2010. WHO, Geneva, Switzerland.

3.       World Health Organization (2016) Global report on diabetes. WHO, Geneva, Switzerland.

4.       Beaglehole R, Bonita R, Horton R, Adams C, Alleyne G, et al. (2011) Priority actions for the non-communicable disease crisis. Lancet 377: 1438-1447..

5.       Báez GD, Piccirilli GN, Ballerini GA, Frattini A, Busti PA, et al. (2017) Physicochemical Characterization of a Heat Treated Calcium Alginate Dry Film Prepared with Chicken Stock. J Food Sci 82: 945-951.

6.       Stone H, Bleibaum RN, Thomas HA (2012) Sensory Evaluation Practices. (4^th edn), Elsevier, London.