Digital ph meter

The water sample was collected, transported and analyzed for physico-chemical parameters according to standard APHA protocol³⁸ . All analysis were ensured with known standards and experiments done in triplicates. The pH and electrical conductivity (EC) were measured using digital pH meter (Hanna, India). The turbidity of water was measured nephelometrically and expressed in NTU. The titrimetric method was used to analyze hardness (EDTA titration), alkalinity (phenolphthalein and methyl orange titration) and chloride (Mohr’s method). Phosphate, nitrate-nitrogen, and ammonia nitrogen were analyzed using UV-VIS spectrophotometer (Hitachi, U 2910-2J1-0012, Japan). Phosphate was analyzed by stannous chloride method, nitrate was measured using brucine – sulphanilic acid method and ammonia nitrogen by Nessler’s method following standard procedures.

The pH values were measured with a digital pH meter (Hanna Instruments, Woonsocket, RI, USA). The pH meter was calibrated with pH 7 and 4 buffers before pH determination. The stainless-steel blade was fitted to the solid sample probe to facilitate penetration into the meat. Cutting the meat allowed direct contact between the probe and the sample, so that the pH was measured directly without further sample preparation. The initial pH of the steaks was measured 2 h after opening the vacuum bag and the initial pH of the brine was measured 3 h after preparing the solution. The pH of the steaks and brine was measured again after the marinating time of each sample. After cooking (24 h), the pH of the steaks was determined three times on each sample [24 ].

Color parameters (L*—brightness, a*—greenness/redness and b*—blueness/yellowness) were measured in the CIELAB space using a portable colorimeter (CR-600d, Minolta Co. Ltd., Osaka, Japan). The device was set to pulsed xenon arc lamp, 10° viewing angle geometry, and 8 mm aperture. The pH was measured in the deer burgers using a digital pH-meter (Hanna Instruments, Eibar, Spain) equipped with a penetration glass probe.

Stirred yogurt samples supplemented with different microcapsules were analyzed according to AOAC⁴⁶ for evaluated stirred yogurt content of dry matter, protein, fat, and ash. The titratable acidity was assessed as illustrated by Ling⁴⁷ . The digital pH meter (Hanna, Germany) was used to evaluate the pH of stirred yogurt samples. All chemical characteristics were determined for 30 days of cold storage at weekly intervals.

Free E, free G-Ppy NPs, and E-G-Ppy NPs were all formulated in a 3% carboxymethylcellulose (CMC) hydrogel base as described by Fadel et al. [13 (link)]. The concentration of E in free E hydrogel and E-G-Ppy hydrogel was 0.03455% w/w and the concentrations of G-Ppy in G-Ppy hydrogel and E-G-Ppy hydrogel were equivalent. The produced hydrogels were visually examined for appearance and uniformity. The pH values of the produced hydrogels were determined using a digital pH meter (HANNA, RI, USA). Samples from different areas of the free E and E-G-Ppy NPs hydrogels were taken, diluted with distilled water, and measured colorimetrically at 515 nm for the study of hydrogel uniformity and the actual E concentration.

A Genway 7300 spectrophotometer (Cole-Parmer Ltd., Staffordshire, UK) was used to record UV–visible spectra. ICP-OES analysis was performed with an Agilent 5100 ICP-OES (Agilent Technologies, Melbourne, Australia). Table 1 shows the operating conditions of ICP-OES for Sm³⁺ determination. A digital pH meter was used to take the readings (Hanna Instruments Inc, RI, USA). To speed up the phase separation, a commercial centrifuge (Hinotek Technology Co., Ningbo, China) was used.Table 1

ICP-OES operating conditions for analysis of samarium

Rf generator power	Plasma gas flow rate	Auxiliary gas flow rate	Nebulizer gas flow rate	Delay time	Integration time	Wavelength
1200 W	12 L min−1	1.0 L min−1	0.7 L min−1	15 s	3 s	359.160 nm

The proximate composition of initial skim milk was performed using Lactoscan spectroscopy technology (Bently Instruments, Inc., MN, USA). AOAC [30 ] methods were used to determine total nitrogen (AOAC, 2000 method 991.20; 33.2.11), non-protein nitrogen (AOAC, 2000 method 991.21; 33.2.12) and non-casein nitrogen (AOAC, 2000 method 998.05; 33.2.64) in SMS using the Kjeldahl method [30 ]. The total protein, cfv NCN, and NPN protein were calculated as nitrogen and multiplied by 6.38. Proximate analyses were performed at 0, 1, 2, 6, 12, and 24 h. A digital pH meter (Hanna Instruments, Inc., Woonsocket, RI, USA) was used for the determination of the pH of SMS (control and rennet-added samples), as described by the method given in (AOAC, 2000 method 973.41) [30 ].