Low-Fat Salad Dressing as a Potential Probiotic Food Carrier Enriched by Cold-Pressed Tomato Seed Oil By-Product: Rheological Properties, Emulsion Stability, and Oxidative Stability

Effect of Inulin on Rheological Properties and Emulsion Stability of a Reduced-Fat Salad Dressing

This study is aimed at investigating the potential use of inulin in a reduced-fat salad dressing to improve its rheological properties, fat globule size distribution, and emulsion stability. The reduced-fat salad dressing, which has 50% less fat compared to the full-fat counterpart (control), was prepared with varying inulin concentrations (10, 12.5, 15, 17.5, and 20% w/w). The full-fat and reduced-fat salad dressings exhibited a non-Newtonian shear-thinning behavior. Power law model was used to describe the rheological properties. Results showed that the flow behavior index (n) and consistency coefficient (K) were greatly affected by the concentration of inulin. A greater pseudoplasticity and apparent viscosity of the reduced-fat samples were achieved with a higher concentration of inulin. Oscillatory tests showed that the storage modulus (G') and loss modulus (G ″) values increased with increasing inulin concentration. All samples displayed characteristics of a viscoelastic solid, as evidenced by a greater G' than G ″. Regarding the size distribution of the oil droplets, the reduced-fat salad dressing containing a higher inulin content was observed to have a larger droplet size. All reduced-fat samples, similar to the full-fat counterparts, exhibited stability with no cream separation over one month of storage at 4°C, as determined by visual observation. Additionally, the reduced-fat salad dressings supplemented with 17.5 and 20% inulin exhibited stability against cream separation, comparable to the full-fat counterpart (p > 0.05), as measured by the thermal stress test (80°C for 30 min) with centrifugation. The sensory acceptance scores for reduced-fat salad dressing with 15 and 17.5% inulin, ranging from approximately 6.28 to 7.63 on a 9-point hedonic scale for all evaluated attributes (appearance, color, aroma, texture, taste, and overall acceptability), were not significantly different from those of the full-fat counterpart (p > 0.05). This study demonstrated that inulin may be a suitable ingredient in reduced-fat salad dressings.

Isolation of Protein and Fiber from Hot Pepper Seed Oil Byproduct To Enhance Rheology, Emulsion, and Oxidative Stability of Low-Fat Salad Dressing

This research aimed to explore the potential utilization of protein (P) and fiber (F) extracted from cold-pressed hot pepper seed oil byproduct (HPOB) in the enhancement of the rheological properties, emulsion stability, and oxidative stability of a low-fat salad dressing with 10% oil content. The assessment involved the examination of several aspects, including the physical qualities such as emulsion stability, rheological behavior, and particle size as well as the microstructure and oxidative stability. It is worth mentioning that all emulsions had desirable characteristics, including shear-thinning behavior characterized by a consistency index ranging from 6.82 to 22.32 Pa s, as well as viscoelasticity and recoverability. These qualities were notably improved with the addition of P and F of HBOP. During the thermal stability testing, it was observed that the low-fat dressing containing 1% P-1F exhibited minor changes in the G* value, indicating its exceptional emulsion stability. The control salad dressings in C1 samples contained 30% oil. (B): C2: samples containing 10% oil (low-fat salad dressing sample) exhibited ζ-potential values of -34.70 and -46.70 mV. The samples 1P-1F and 2P-1F exhibited the highest ζ-potential values. Furthermore, the increase in F resulted in a reduction in droplet size and elicited elevated values for the induction period (IP), with the exception of samples containing 1% protein, 3% fiber, and 10% oil (1P-3F). The salad dressings that included P-F exhibited enhanced oxidative stability, demonstrated by their longer IP (ranging from 5.11 to 7.04 h) compared to the control samples. The formulation consisting of samples contained 1% protein, 1% fiber, and 10% oil (1P-1F) and samples contained 2% protein, 1% fiber, and 10% oil (2P-1F) exhibited superior ζ-potential, emulsion stability, and recovery rate compared to other formulations. The findings of this investigation indicate that the interaction of proteins and fibers extracted from HPOB exhibits the potential to enhance the rheological characteristics, emulsion stability, and oxidative stability of low-fat salad dressing.

Capsaicin Rich Low-Fat Salad Dressing: Improvement of Rheological and Sensory Properties and Emulsion and Oxidative Stability

This study aimed to investigate the potential use of cold-pressed hot pepper seed oil by-product (HPOB) in a low-fat salad dressing to improve its rheological properties, emulsion, and oxidative stability. The total phenolic content (TPC), the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and CUPRIC reducing antioxidant capacity (CUPRAC) values were 317.4 mg GAE/100 g, 81.87%, and 6952.8 mg Trolox/100 g, respectively. The capsaicin, dihydrocapsaicin, and total carotenoid content were 175.8 mg/100 g, 71.01 mg/100 g, and 106.3 µg/g, respectively. All emulsions indicated shear-thinning, viscoelastic solid-like behavior, and recoverable characteristics, which were improved via enrichment with HPOB. The thermal loop test showed that the low-fat sample formulated with 3% HPOB indicated little change in the G* value, showing that it exhibited high emulsion stability. The induction period values (IP) of the salad dressing samples containing HPOB (between 6.33 h and 8.33 h) were higher than the IP values of the control samples (3.20 h and 2.58 h). The enrichment with HPOB retarded the formation of oxidative volatile compounds of hexanal, nonanal, and 1-octene-3-ol. According to the results presented in this study, HPOB could be effectively used in a low-fat salad dressing to enhance its rheological characteristics and oxidative stability.