Effects of High-Pressure Homogenization on the Structural, Physical, and Rheological Properties of Lily Pulp

Abstract

The effects of high-pressure homogenization (HPH) on the structural, physical, and rheological properties of lily pulp (15%, w/w) were investigated. Different pressures ranging from 0 MPa to 100 MPa were used. The focus was on evaluating the changes in the particle size distribution (PSD), structure, pulp sedimentation behavior, serum cloudiness (SC), total soluble solids (TSS), color, and rheological behavior of the pulps. PSD analysis showed that the diameter of suspended lily particles significantly decreased with an increasing homogenization pressure. The suspended particles observed through optical microscopy became small after homogenization, highlighting the effect of HPH on disrupting the suspended particles. Compared with the untreated pulp, the SC and sedimentation velocity of the homogenized pulps decreased due to the disruption of the suspended particles. The effects of HPH on the sedimentation index and SC exhibited an asymptotic behavior similar to that of the changes in the particle size of lily pulp. Moreover, HPH processing reduced the viscosity of lily pulp and increased the TSS and lightness of the homogenized pulps. HPH significantly modified the structural, physical, and rheological properties of lily pulp. The pulp homogenized above 60 MPa had good suspension stability. This finding indicates that HPH technology can be used to improve the stability of lily pulp.

Physical Stability of Lotus Seed and Lily Bulb Beverage: The Effects of Homogenisation on Particle Size Distribution, Microstructure, Rheological Behaviour, and Sensory Properties

“…Compared with the sample under 0 MPa, the PSD span of those under 20 and 40 MPa were significantly reduced, which represented the width of the PSD, with smaller values indicating a narrower distribution [ 23 ]; however, the samples under 60~100 MPa had a significantly higher span than those under 0~40 MPa ( p < 0.05). This is contrary to the findings of Liu et al [ 30 ], who reported a narrower distribution of PSD with increasing pressure on homogenised lily pulps from 20 to 100 MPa, possibly because two composite raw materials, lily bulbs and lotus seeds, were used in our study and that homogenisation preferentially crushed one of the more friable materials, resulting in a slightly larger measured span value. Moreover, the particle diameter decreased while the number of particles increased after homogenisation treatment, which increased the number of contact points among the particles due to mechanical and chemical interactions [ 23 ].…”

“…Figure 1 illustrates the effect of several homogenisation pressures on the particle size distribution of LLB samples. As shown in Figure 1a, the average particle size of LLBs is reduced after the homogenisation treatment, which is consistent with the observations in previous studies on fruit and vegetable products, such as lily pulps [30], rosehip nectar [24], tomato juice [31] and blackcurrant juice [32]. Gul et al found that cavitation, friction, shear, and turbulence phenomena were generated after homogenisation, and as the homogenisation pressure increased, suspended particles such as cellular debris, polymers, and fibrous particles in the samples were further broken down into smaller sizes [33].…”

Impact of Innovative Technologies on the Content of Vitamin C and Its Bioavailability from Processed Fruit and Vegetable Products

“…This method is used on liquid products, where the rheological properties of the product change under the influence of high pressures [ 69 , 70 ]. The process allows the solid particles in the suspension to be broken down, thanks to which the product acquires a uniform, smoother consistency [ 71 , 72 ].…”

Lily Starch—An Underutilized and Non‐Conventional Source: Properties and Applications

“…[81] Many documented studies have shown that HPH processing causes alterations in the particle size, particle shape, and particle size distribution of samples and eventually controls the total physical properties and rheological mannerism of samples. [82] In previously documented results, when HPH has a serious impact on the properties of various starches, the conditions utilized were different from those used for lily starch, especially the concentration of the starch suspension and the magnitude of the pressure. The reported impact of HPH on lotus seed starch [5] and corn starch [83] induces a reduction of molecular weight, enhancement of thermal and pasting properties, and digestion, and the extent of these manifestations depend on applied pressure, starch concentration, botanical origin, and treatment time.…”

“…[ 81 ] Many documented studies have shown that HPH processing causes alterations in the particle size, particle shape, and particle size distribution of samples and eventually controls the total physical properties and rheological mannerism of samples. [ 82 ]…”