Optimising functional properties and chemical composition of Pinus halepensis Mill. Seeds protein concentrates

Abstract

Vegetable proteins are widely used in many food formulations due to their physico-chemical properties, low cost and availability. The main objective of this work is to study the chemical composition and properties of a protein concentrate of Pinus halepensis. Mill seeds (PHPC) and mainly to optimize the effect of pH, NaCl concentration and phosphate buffer (PB) molarity on functional properties (solubility, emulsifying activity index (EAI) and foaming capacity (FC)) of this concentrate by response surface methodology (RSM). The chemical composition was determined in terms of proteins, sugars, lipids, ash and moisture. The physico-chemical characteristics were studied by their water and oil holding capacity (OHC, WHC) and their surface hydrophobicity (SH). Finally, the functional properties of PHPC were studied in terms of solubility, EAI, FC, minimum gelling concentration (MGC) and finally heat coagulability (HC). A PHPC yield of 36.66 �0.7% was obtained. The WHC and OHC was 3.89 g water/g PHPC and 3.54 g oil/g PHPC respectively and a SH of 87.09 �0.78 was obtained. The optimization results showed that the optimal conditions for solubility, EAI and FC were: pH:10.88, NaCl:0 g/l, PB:0.078 M; pH:12, NaCl:0.55 g/l, PB:0.1M and pH:2, NaCl:0, PB:0 M respectively, having given a solubility of 87.13 �0.14%, an EAI of 36.82 �0.34 and a FC of 182.72. Then, the desirability of the three responses (solubility, EAI and FC) which was pH:12, NaCl: 0.55 g/l and PB of 0.1M was used to assess the stability of EAI and FC, to determine the MGC and HC. This study shows that Aleppo pine seeds are a good source of functional proteins, potentially applicable in the food industry and that pH, NaCl concentration and PB molarity have a major influence on functional properties.