Preparation of protein powder from the liver of Yellowfin tuna (Thunnus albacores): a comparison of acid- and alkali-aided pH-shifting

Abstract

For the high-value utilization of tuna liver, the effects of acid-aided (Acid-pH) and alkali-aided pH-shifting (Alkali-pH) on the physicochemical and functional properties of the protein powder prepared by pH-shifting and freeze-drying were studied. As expected, the protein powder with high purity could be obtained through Acid-pH or Alkali-pH followed by freeze drying, while the Alkali-pH led to a higher protein yield, higher protein ratio, lower lipid ratio and lower heavy metal content than Acid-pH. The amino acid profile of the protein powder prepared by Alkali-pH (Alkali-PP) was similar with that prepared by Acid-pH (Acid-PP). In addition, compared with Acid-PP, the Alkali-PP possessed the greater capacities in emulsion activity, foaming capacity and fat absorption capacity. Furthermore, the foaming capacity, foam stability and fat absorption capacity of Alkali-PP was better than soy protein powder. Therefore, Alkali-pH followed by freeze-drying would be a better alternative to prepare high-quality protein powder from tuna liver in the food industry.

Bioactive peptides-derived from marine by-products: development, health benefits and potential application in biomedicine

“…In addition, due to intense heat and pressure, this process diminishes the product's functionality (Petrova et al, 2018;Zamora-Sillero et al, 2018). On the other hand, alkali hydrolysis uses calcium, sodium, or potassium hydroxide as alkaline agents to divide (Melgosa et al, 2020;Petrova et al, 2018;Shen et al, 2021;Surasani, 2018) Mackerel whole body Recovered protein 49.48% with HCl 0.1 M (Álvarez et al, 2018) Baltic herring whole body Protein yield 30.0% at pH 2.5 (Nisov et al, 2022) Cod (head, tail, bones) (Álvarez et al, 2018;Melgosa et al, 2020;Petrova et al, 2018;Shen et al, 2021;Surasani, 2018;Villamil et al, 2017;Zamora-Sillero et al, 2018) Mackerel DH 12.6% (Nikoo et al, 2021a) Enzymatic hydrolysis: Bui et al, 2021;Mongkonkamthorn et al, 2020;Saidi et al, 2018;Zhang et al, 2019b) • High specificity (Ghorbel-Bellaaj et al, 2018;Guo et al, 2019;Mechri et al, 2020;Nugroho et al, 2020;Rajendran et al, 2018) • Bacterial growth Fisheries and Aquatic Sciences protein molecules. In contrast to acidic hydrolysis, alkali hydrolysis requires a less extreme working environment, for instance 54℃ (Melgosa et al, 2020;Petrova et al, 2018).…”

Simultaneous separation of protein and oil from the liver of sturgeon ( Acipenser baerii ) by three‐phase partitioning

“…The amino acids of TPP protein and pH‐shift protein were analyzed following the method of Shen et al. (2021) with some modifications. First, the sample was subjected to acidic hydrolysis (mixed with 6 mol/L HCl, 110°C and 18 hr).…”

Profiles of sturgeon protein prepared by two methods and the correlation between protein fractions and functional properties

“…So far, the mainstream view is that the aforementioned differences are due to the diverse denaturation degrees of protein which can result from different preparation methods. Regarding various raw materials, protein with better functional properties can typically be obtained by Alkali‐pH than by Acid‐pH, and the relevant scholars have all attributed this to the more serious denaturation degree of protein in acidic conditions (Surasani, 2018; Shen et al., 2022; Tang et al., 2021). Furthermore, the extreme pHs used in pH‐shift result in a reduction in the functional properties of protein obtained, which has also mainly been explained by the more severe degree of denaturation under extreme conditions (Abdollahi & Undeland, 2019; Cha et al., 2020).…”