Effect of Different Sterilization Methods on the Microbial and Physicochemical Changes in Prunus mume Juice during Storage

Abstract

This study evaluated the pasteurization (P), ozone (O3), ultrasonic (US), and high-hydrostatic-pressure (HHP) sterilization approaches for processing of Prunus mume regarding browning factors and microorganisms, compared with non-sterilization (control check, CK) treatment. The microorganisms (total bacterial count and fungi and yeast count) in the juice were identified after different sterilization techniques, while the quality parameter changes (degree of browning, color measurements, total phenolic content, reducing sugar, ascorbic acid, 5-hydroxymethyl furaldehyde (5-HMF), amino acid nitrogen, total soluble solids (TSS), pH value) were investigated. The results indicate that P and HHP treatment reduced non-enzymatic browning while substantially impacting the color measurements, TSS, and pH, while the sterilization effect was remarkable, with a rate exceeding 90%. Furthermore, the Prunus mume juices treated with P and HHP sterilization were used as the objects, and the CK group was used as the control group. They were placed at 4 °C, 25 °C and 37 °C, respectively, and stored in dark for 15 d. Sampling and determination were carried out on 0, 3, 6, 9, 12, and 15 d, respectively. M-&-Y (molds and yeasts) were not detected in the late storage period, and no obvious microbial growth was observed during storage, indicating that P and HHP treatments could ensure the microbial safety of Prunus mume juice. P- and HHP- treated Prunus mume juice has better quality and low temperature storage is beneficial for maintaining the quality of Prunus mume juice. Therefore, P treatment or HHP treatment combined with low temperature storage could achieve a more ideal storage effect. Overall, this study conclusively established that P and HHP methods were suitable for sterilizing Prunus mume juice. These techniques minimally affected overall product quality while better maintaining the quality parameters than the untreated juice samples and those exposed to O3 and US treatment.

Effect of combined ultrasonic and enzymatic extraction technique on the quality of noni (Morinda citrifolia L.) juice

“…Similar results were also reported in orange [38] and strawberry juice [39] treated with ultrasound. The brightness of noni juice after EZ treatment dropped significantly compared with the CON, which may be due to the enzymatic browning caused by long-time enzymatic treatment and non-enzymatic browning induced by the heating process of enzyme elimination [40] , [22] . Under combined enzymatic and ultrasonic treatment, the greeness of juice sample decreased obviously, while the yellowness increased significantly.…”

“…Subsequently, the absorbance at 625 nm was recorded using a microplate reader (Synergy LX, Biotek, USA). The reducing sugar content was assessed using 3, 5-dinitrosalicylic acid (DNS) method slightly modified from Ma et al [22] . The juice sample or glucose standard solution was added to 200 μL of DNS regent and maintained in boiling water for 5 min, followed by rapid cooling in an ice bath.…”

“…The color parameters L* (lightness/darkness), a* (redness/greenness), and b* (yellow/blueness) were measured. In addition, the total color difference (ΔE*), in comparison to CON, was calculated according to the equation (4) [22] : where ΔL*= L* standard - L* sample ; Δa*= a* standard - a* sample ; Δb*= b* standard - b* sample .…”

Quality Characteristics, Anthocyanin Stability and Antioxidant Activity of Apple (Malus domestica) and Black Chokeberry (Aronia melanocarpa) Juice Blends

“…However, in all juices, TSS was significantly ( p < 0.05) higher after four months storage than at the time of processing. The higher TSS content after heat treatment and storage may be attributed to the hydrolysis of polysaccharides (starch and pectic substances) of juices into monosaccharides and other soluble solids under acidic conditions [ 23 , 24 ]. The results are in agreement with the findings of Khan et al [ 25 ], who reported an increase in the TSS of mango–sea buckthorn blended juices after three months storage.…”

Ready-to-Eat Fish Cake Processing Methods and the Impacts on Quality and Flavor

“…Chantakun et al [ 6 ] demonstrated that different heat treatment methods, including pasteurization at a high temperature for a shorter time or at a low temperature for a longer time at 118 °C and 121 °C sterilization, had significant effects on the quality and characteristics of bird’s nest beverages. MA et al [ 7 ] reported that different sterilization methods of Prunus mume juice have significant effects on the microbiological and physicochemical parameters, such as the degree of browning, color measurements, total phenolic content, reducing sugar, ascorbic acid, 5-hydroxymethylfurfural, amino acid nitrogen, total soluble solids (TSS), and pH value during storage.…”