Thanasak Sae-Leaw

The effectiveness of multi-targeted treatments including pulsed electric field (PEF), soursop leaf extract (SLE), vacuum impregnation (VI), and modified atmosphere packaging (MAP), with and without cold plasma (CP) treatment, on the quality and shelf life of Pacific white shrimp (Penaeus vannamei) during refrigerated storage for 21 days was investigated. PEF inhibited melanosis and reduced the initial bacterial load, as evidenced by lower melanosis scores and total bacterial counts in the treated samples. Integrating 1% SLE through VI effectively lowered color alteration, retarded melanosis, and preserved textural integrity in the SLE-treated samples (p < 0.05). SLE1 (1%) significantly reduced lipid oxidation, as witnessed by lower thiobarbituric acid reactive substances (p < 0.05) and minimal fatty acid profile changes. MAP3, comprising CO₂/N₂/Ar (60%/30%/10%), combined with CP treatment, ensured microbiological quality and maintained total viable count within the acceptable limit (6 Log CFU/g) throughout the storage time of 21 days. Notably, the PEF-SLE1-VI-MAP3-CP sample exhibited superior quality preservation, as shown by a lower pH and total volatile base content than the others. Sensory evaluation confirmed that the PEF-SLE1-VI-MAP3-CP sample remained sensorially acceptable during storage. Thus, this multi-hurdle approach demonstrated the synergistic potential of integrating nonthermal processing technologies with plant extracts, contributing to the extended shelf life and safety of the refrigerated shrimp for up to 21 days.

Shrimp has been known for its delicacy, but it undergoes rapid deterioration induced by biochemical and microbiological reactions. Melanosis is a major cause of discoloration associated with consumer rejection. All ethanolic extracts from different leaves including soursop, noni, and Jik leaves were dechlorophyllized via the “Green” sedimentation method before being used. The inhibitory activity against polyphenoloxidase (PPO) from Pacific white shrimp (Litopeneous vannamei) and the copper-chelating properties of varying extracts were compared. Soursop leaf extract (SLE) showed higher PPO inhibitory activity and copper-chelating ability than others (p < 0.05). Based on LC-MS, aempferol-3-O-rutinoside was identified as the most abundant compound, followed by catechin and neocholorigenic acid. The efficacy of SLE at different levels (0.25–1%) for inhibiting melanosis and preserving the quality of Pacific white shrimp was evaluated during refrigerated storage at 4 °C for 12 days in comparison with that of a 1.25% sodium metabisulfite (SMS)-treated sample. SLE at a level of 1% effectively retarded melanosis and bacterial growth, in which the total viable count did not exceed the microbial limit within 12 days. In addition, 1% SLE treatment impeded autolysis, reduced protein degradation and decomposition, and minimized lipid oxidation, as witnessed by the lower increases in pH, TVB-N, and TBARS values. Sensory evaluation indicated higher likeness scores and overall acceptability for SLE-1% and SMS-1.25% shrimps than those of the control and other samples. Therefore, SLE could be used as a natural alternative that effectively lowered the melanosis and quality loss of shrimp during refrigerated storage.

The impact of chrysanthemum tea fortification (1, 3, and 5%, w/v) with hydrolyzed collagen powder (HCP) derived from salmon scale ossein on physicochemical, antioxidant, and sensory properties during 6 months storage at room temperature (30°C) was investigated. Addition of HCP yielded chrysanthemum tea with increased browning index, turbidity, pH, and α-amino group content, especially at higher levels of incorporation. Fortification with HCP increased antioxidant activities, including ABTS and DPPH radical scavenging activities, ferric reducing antioxidant power, and oxygen radical absorbance capacity of chrysanthemum tea in a dose-dependent manner (p < .05). However, continuous decreases in antioxidant activities in all tea samples were observed during storage (p < .05). Fortification with the HCP had no negative impact on acceptability of chrysanthemum tea. Therefore, chrysanthemum tea fortified with HCP could be produced as a functional drink with antioxidant activity having shelf life up to 6 months at 30°C.

Alkaline treatment has been extensively implemented in the extraction process of hydroxyapatite (HAp) extraction from various kinds of bio-materials, such as animal bone and scales. The main purpose of such treatment is to remove proteinaceous substances from raw materials. The influence of the alkaline treatment that could alter not only the organic contents but also chemical composition—specifically the Ca/P mole ratios of bio-calcium, HAp, and the biphasic apatite powders derived from salmon bone, a by-product from the salmon industry—was investigated. Both HAp and biphasic apatite powders were obtained from the calcination of bio-calcium powders with and without alkaline treatment, respectively. An X-ray diffraction analysis confirmed the presence of hydroxyapatite and β-tricalcium phosphate (β-TCP) in the calcined bone powder without alkaline treatment while only a single phase of hydroxyapatite was observed in the alkaline-treated sample. Calcium and phosphorus contents were measured by an inductively coupled plasma optical emission spectrometer (ICP-OES). A variation of Ca/P ratios was observed among all samples, depending on the chemical and heat treatment conditions. Organic molecules, such as protein, fat, hydroxyproline, and TBARS, were significantly lowered in bio-calcium powders with the alkaline treatment. This work represents important research on chemical treatment prior to the raw material conversion process, which significantly influences chemical and phase compositions of the bio-calcium and hydroxyapatite powder derived from salmon bone waste.