T25 basic

For the quantification of the particles’ total phenolic content and the antioxidant activity of the encapsulated pineapple peel compounds, extracts from microparticles were obtained by the method described by Rocha et al. [34 (link)] with some modifications. The spray dried particles (200 mg) were dispersed in 10 mL of methanol and strongly homogenized with an ultraturrax homogenizer (IKA Labortechnik T25 Basic, Staufen im Breisgau, Germany) at 13,500 rpm for 3 min in order to break the particles. The suspension was left at 10 °C, in the dark, for 12 h. Then, the solutions were centrifuged at 7000 rpm, during 15 min at 4 °C and the collected supernatant was stored in amber glass flasks.

Volatile basic nitrogen (VBN) values were measured using the method of Conway [8 ] to determine protein degradation. After a homogenized sample was mixed with 9 mL of double distilled (dd)-water using a homogenizer (T-25 basic; IKA Labortechnik, Staufen, Germany) for 1 min, the mixture was then filtered using a filter paper (Whatman #2; GE healthcare, UK). And then 1 mL of the sample was dispensed into the outer chamber of a Conway cell and 1 mL of a 0.01 N boric acid solution and 50 μL of an indicator (0.066% methylene red + 0.066% bromocresol green) were dispensed into the inner chamber. Then, 1 mL of saturated K₂CO₃ solution (50%) was injected into the outer chamber. Conway cell was quickly sealed, horizontally agitated, and incubated at 37°C for 120 min. After incubation, 0.01 N HCl solution was titrated to the sample. The VBN value was then determined using the following formula.

To obtain the extracts from the encapsulates, the methodology reported by Rocha et al. [41 (link)] was utilized with few modifications. In 10 mL of water, 200 mg of encapsulate was dispersed and was dissolved with an ultraturrax (IKA Labortechnik, T25 Basic, Staufen, Germany) for 3 min at 13,500 rpm. This suspension was left in the dark for 2 h and subsequently centrifuged for 15 min at 5000 rpm; the supernatant was used for further analysis.

Volatile basic nitrogen (VBN) values of sausage samples were determined according to the method of Conway [17 ]. Briefly, after the ground sample (1 g) was added to 9 mL of double distilled (dd)-water and blended with a homogenizer (T-25 basic; IKA Labortechnik, Staufen, Germany) for 1 min, the mixture was filtered using a filter paper (Whatman #2; GE healthcare, UK). Filtered sample (1 mL) was injected into the outer chamber of a Conway cell, whereas boric acid solution (0.01 N, 1 mL) and indicator solution (0.066% methylene red and 0.066% bromocresol green, 50 μL) were injected into the inner chamber. Saturated K₂CO₃ solution (50%, 1 mL) was then injected into outer chamber. The chamber was sealed and incubated at 37°C for 120 min. A HCl solution (0.01 N) was titrated to samples until color turned to violet red. VBN values were derived by substituting titrated amount of HCl solution to the formula as followed:

A basic storage design was performed to study shelf life [10 (link)] in pasta developed throughout the determination of fatty acid profiles and chemical parameters (TBARS and acidity index). Fatty acid profiles were determined according to Bligh and Dyer, 1959 [29 (link)]. Firstly, each sample was homogenized with an Ultraturrax device (IKA-WERKE, T-25 basic) using different solvents such as chloroform, methanol, potassium chloride, and water. This mixture was centrifuged for 10 min at 4000 rpm, and the fat was extracted from the top, and afterwards, after incorporating BHT, butylated hydroxytoluene, as an antioxidant substance, solvents were evaporated with nitrogen gas. Afterwards, methylation was performed using 0.03 g of this previous fat. This fat was mixed with an intern pattern, C23:0, which does not caused interferences in the matrix. Then, 2 ml of hexane and 1 ml of potassium hydroxide saturated solution in methanol was added. The upper phase was extracted to measure. To analyze the fatty acid profile, a gas chromatograph (HP-6890 II Hewlett-Packard) was employed with a column SP-2380 (100 m × 0.25 mm × 0.20 µm). The temperature program was 140–165 °C at 3 °C/min during 10 min and 165–220 °C at 5 °C/min during 50 min. Fatty acid content was quantified as total area (%) of identified fatty acids.