Nutritional analysis and evaluation of the consumer acceptance of pork pâté enriched with cricket powder - preliminary study

Abstract The growing interest in insects as food ingredients on the one hand is controversial, on the other is in line with the recommendations of international organizations, such as the Food and Agriculture Organization of the United Nations. Crickets, as well as cricket powder (CP), are a source of high quality protein, fat, vitamins and minerals. This paper analyzes the impact of CP additive (2%, 6% and 10%) on the nutritional value and consumer acceptance of enriched pâtés. It was shown that the CP additive significantly increases the content of protein, fat and minerals. It also changes the color of the product, which is darker (lower L* value), and the color balance is shifted towards the blue. Consumer assessment showed that the 2% CP additive allows to obtain a product of high attractiveness for consumers.

The FAO recommends the use of insects as food, due to the easily digestible protein (FAO 2013). Due to the growing costs of animal protein production (Ivanic and Martin 2008), it seems particularly interesting to use insect protein in the production of food for athletes. such snacks can be purchased in Great Britain, France or the Netherlands. Unfortunately, for cultural reasons, the inhabitants of most Western European countries are reluctant to eat insects and products made from them.
Greater availability of information on the potential nutritional benefits of using edible insects would allow the development of new products and thus the fulfillment of consumer preferences in this direction (House 2016;Pambo et al. 2018). Additives used to improve the nutritional value of pâtés or give them new health-promoting properties may, however, change its physicochemical characteristics (Baranowska 2011;Baranowska et al. 2018), and this may lead to changes in the attractiveness of enriched products. Therefore, the aim of this work was to evaluate the impact of cricket powder addition on the sensory attractiveness of pork pâté, as well as its nutritional value.

Pâté manufacturing
Cricket powder (CP) was bought from Crunchy Critters (United Kingdom) and it contained 56.8% protein, 29.3% fat, 5.5% carbohydrates and 2.3% fiber. Pâtés were prepared using meat, liver and fat from pork (Mas-Pol, Poland), CP and a mix of spices consisting of pepper, dried onion, marjoram (McCormick Polska S.A., Poland). Pork meat (38.96%) and fat (24.35%) were boiled in water until tender. The material prepared in this way was pre-grated in a PT-98 type mincer (Mainca, Spain) using a 3 mm mesh. After that, the meat was combined with the hot broth (19.48%) obtained during cooking of meat and spice mix (2.60%) and mixed in a bowl cutter Mainca,Spain) at 55°C. Homogenized pork liver (14.61%) was added to the minced meat and the grinding operation was continued until homogeneous consistency was obtained. Finally, the mass was placed in 200 mL jars and cooked at 70°C for 40 minutes. Thus prepared pâtés were cooled with cold water and stored in a refrigerator prior to the analyses. The pâté formulations contained 2%, 6% and 10% addition of cricket powder (added together with spice mix), and were termed CP2, CP6 and CP10, respectively. Pâté without CP addition was used as a reference (R).

Nutritional composition and energy value
The ash content was determined according to ISO 936, total water content -according to ISO 1442, fat content (Soxhlet method) was determined according to ISO 1444. Total nitrogen content was determined by the Kjeldahl method according to ISO 8968 and was used to calculate the protein content by multiplying the result by the conversion factor of 6.25. Moreover, the proximate carbohydrate content was estimated by subtracting the total fat, protein, ash and moisture content from 100%. The energy value [kcal/100 g] was calculated with the following formula: energy value = 4 × protein (%) + 4 × carbohydrate (%) + 9 × fat (%).

Color measurements
The color of the pâté was measured using a Chroma Meter CR-410 (Konica Minolta Sensing Inc., Japan) color meter. Differences were recorded in CIE L*a*b* scale in terms of lightness (L*) and color (a* -redness; b* -yellowness) . Moreover, the total color difference (ΔE) was calculated using the formula:

Consumer acceptance
Thirty untrained panelists for organoleptic assessment (basic flavors, color vision, odor detection, tactile sensitivity), as well as the ability to communicate sensory product descriptions in accordance with the recommendations of ISO 8589 were invited to participate in this study. Consumer rating was evaluated according to a 10-cm linear scale (Villanueva et al. 2000). Consumers, in the age between twenty and forty-five, were asked to evaluate the color on the cross-section: intensity (from light to dark), uniform; texture: consistency, uniform, spreadability; flavor: meat, fat, salty, liver, bitter, other; odor: meat, liver, other; and overall rating as well.

Statistical analysis
All the measurements were repeated three times, unless stated otherwise. One-way analysis of variance (ANOVA) was carried out independently for each dependent variable. A post-hoc Tukey HSD multiple comparison test was used to identify statistically homogeneous subsets α = 0.05. Statistical analysis was performed with Statistica 13 software (Dell Software Inc., USA).

Ethical approval:
The conducted research is not related to either human or animal use.

Results and discussion
The interest in using insects for food production is rising in Europe. Edible insects, as well as products obtained from them, including cricket powder, are a good source of high quality protein, but also fat and vitamins (Ayieko et al. 2016). Moreover, the main advantage of farming edible insects is that they do not have to be fed on grains, thus saving agricultural land for growing crops for human consumption (van Huis 2013). The use of CP for food production can, on the one hand, reduce production costs, and on the other, provide many nutrients. Unlike other proteins of animal origin (poultry, pork or beef), the production of an insect protein has a smaller ecological footprint (Dobermann et al. 2017). Another advantage is the possibility of using waste from the agri-food industry as feed for insects. It enables reduction of production costs and makes the process independent of the raw material used as food by people (Lundy et al. 2015). All these advantages make the cricket additions not only an additive that is cheap, healthy and functional, but also environmentally friendly. According to the assumptions, the CP additive caused a significant increase in the protein content in the obtained pâtés (Table 1). Analogous results were observed in the case of fat content. Crickets contain also microelements (Finke 2007;Stull et al. 2018;van Huis 2013), thus the addition of CP caused a significant increase in mineral content. Due to the high fat content in CP, the effect of using the additive on the energy value of pâtés was also observed.
The lightness (L * ) was reduced in pâtés containing CP therefore they were darker (Table 2). There were slight changes in the value of parameter a * , but the blue/yellow balance, which represents parameter b * , has shifted toward blue in CP2, CP6 and CP10. Also, total color differences (∆E) were calculated for pâtés with cricket powder. Mokrzycki and Tatol (2011) proved that an experienced observer may visually detect color deviation when ∆E is greater than 3.5 between 2 objects. The results obtained (∆E = 5.50, 10.53 and 17.10 for CP2, CP6 and CP10, respectively) allow a statement that pâtés with CP deviated very much from reference samples. The color of food products is one of the key parameters on the basis of which consumers choose the product. Thus, it is extremely important that the additives used do not cause significant color changes in relation to the conventional product (Grunert 1997).
Changes in the proximate composition has a significant impact on the quality of products, understood not only as physicochemical but also as sensory properties (Jin et al. 2014;Steen et al. 2014). Moreover, commercial success of Mean values denoted by different letters differ statistically significantly (p < 0.05). new ingredients, and thus products, relies on consumer acceptance (Sun-Waterhouse and Wadhwa 2013). The analytically determined differences between reference pâté and pâtés with cricket powder were reflected in the consumer assessment (Table 3). One of the most important features influencing the consumer's decision to buy a product is appearance, taste and flavour. It was shown that the CP additive affects the sensory characteristics of the enriched pâté. The reference product had the highest rating in terms of appearance, compared to all enriched pâtés. The CP additive changed the color, which resulted in worse acceptance among consumers. A negative effect of the additive on the taste and flavor assessment was also observed. With the increase in the amount of CP additive, the palatability of meat and liver in taste and flavor decreased, while the saltiness and palpability of others taste and flavor increased. Surprisingly, however, it turned out that the addition of CP improves the texture according to consumer ratings. The CP10 and CP6 variants received significantly higher texture ratings for consistency (7.7 and 7.5, respectively) and uniform (5.1 and 4.8, respectively) compared to the reference sample (4.9 for consistency and 3.2 for uniform). At the same time, a reduction in the spreadability rating was noted.

Conclusion
It was found that the addition of cricket powder influences the proximate composition, increasing the content of ash, fat and protein in the final product. The additive used also changed color determinants. It caused reduction in lightness of pâtés and shifted color balance toward blue. Taking into account the slight change in sensory acceptance, a small amount of cricket powder additive can be used in the production of sensitively attractive pâté. Nevertheless, further studies on the impact of cricket powder additive on the texture, structure and properties of pâtés are needed to explain the changes in the attractiveness of enriched products observed in this work.