Pijuayo (Bactris gasipaes) pulp and peel flours as partial substitutes of animal fat in burgers: Physicochemical properties

The high intake of food with a high fat content rich in saturated fat has been recognized as a risk factor for the development of cardiovascular diseases, obesity, diabetes, and gastrointestinal cancers. Peach palm (Bactris gasipaes), known as pijuayo in Peru, is a native fruit from the Peruvian Amazon and has a nutritional value because of its unsaturated fatty acids, fiber and carotenoids content. The incorporation of peach palm (PP) as food ingredient could have technological and nutritional implication as a fat substitute in food products. In this context, the aim of this study was to evaluate the incorporation of PP flour, obtained from the pulp and peel of PP, as substitutes of animal fat in beef-based burgers. The flours were obtained by cooking PP in boiling water for 30 min, separating the pulp from the peel and drying both pulp and peel, separately, in an oven with circulating air at 55 °C until reach a moisture < 15%. Five treatments were prepared varying the substitution of pork backfat: 0% substitution (T1), 25% (T2) and 50% (T3) substitution with PP pulp flour, and 25% (T4) and 50% (T5) substitution with PP peel flour. A randomized complete block design (the block was the repetition of the burger processing in three independent days) was carried out. The instrumental texture profile, proximal analysis, cooking losses, diameter reduction and lipid oxidation by TBARS (after 15 days of storage at 4 °C) were evaluated. Data were analyzed using ANOVA and Tukey post hoc test at 5% of significance. The results showed that the hardness and chewiness decreased significantly by the incorporation of PP flours, regardless of the level of fat substitution. There were no differences between treatments regarding the proximal composition of burgers, with the exception of fat content. Burgers with PP peel flour stood out for having the lowest fat content (9.4–9.6%) compared to the other treatments (p < 0.05). For all treatments: moisture level ranged from 60.3–63.6%, protein from 14.3–15.9%, carbohydrate from 4.8–8.9%, and ash from 2.4–3.0%. Moreover, PP peel flour also had the lowest cooking losses (10.3–11.7%), diameter reduction (15.2–16.0%), and TBARS values (0.135–0.224 mg malondialdehyde/kg) (p < 0.05). In conclusion, PP fruit has the potential to be utilized as new ingredient in burgers, but future studies are needed regarding detailed sensory trials and consumer acceptance, as well as a pilot scale study to evaluate their potential industrialization.