Optimization of Formulation Stabilizer and Analysis of Volatile Component in Fermented Walnut Milk

Herein, walnut without pellicle was utilized as the raw material for the production of fermented walnut milk. The factors affecting quality of fermented walnut milk were investigated. The formulation of stabilizer in fermented walnut milk was optimized by a single factor experiment and orthogonal test with the amount of carboxymethylcellulose sodium (CMC-Na), pectin and gellan gum as investigation factors. The stability index and sensory score were used as evaluation indices. Gas chromatography-mass spectrometry (GC-MS) combined with headspace solid-phase microextraction (HS-SPME) was used to characterize the volatile profile of walnut milk before and after fermentation. The results showed that the optimal formulation was 2.5‰ CMC-Na, 1.1‰ pectin and 0.3‰ gellan gum. Under these conditions, the walnut milk exhibited good stability and sour-sweet and delicious taste with the stability index 1.1 and sensory score 94.5. There was a great variability in aldehydes, ketones and alcohols and the aroma quality of walnut milk was significantly improved.