Please use this identifier to cite or link to this item: http://kb.psu.ac.th/psukb/handle/2016/19122
Title: Chamuang (Garcinia cowa Roxb.) Leaf Extract and Selected Non-thermal Processing Technologies for Inhibition of Melanosis and Quality Changes of Pacific White Shrimp (Litopenaeus vannamei) during Refrigerated Storage
Authors: Soottawat Benjakul
Khursheed Ahmad Shiekh
Faculty of Agro-Industry (Food Technology)
คณะอุตสาหกรรมเกษตร ภาควิชาเทคโนโลยีอาหาร
Keywords: Food Cooling;Food Preservation
Issue Date: 2020
Publisher: Prince of Songkla University
Abstract: Inhibition of Pacific white shrimp (PWS) polyphenoloxidase (PPO) with Chamuang leaf extract (CLE) was studied. CLE was rich in polyphenolic glycosides, in which chrysoeriol 6-C-glucoside-8-C-arabinopyranoside and 2-feruloyl- sinapoylgentiobiose were dominant. It also contained organic acids including hydroxycitric acid and oxalosuccinic acid. CLE with copper chelation activity could inhibit PPO in a dose dependent manner. PWS treated with 1% CLE had the lower melanosis score than 1.25% sodium metabisulfite (SMS) treated sample and the control throughout the refrigerated storage of 12 days at 4 °C (p<0.05). Lower total volatile base (TVB) and thiobarbituric acid reactive substances (TBARS) along with lower counts of microbial (mesophile, psychrophile) and spoilage bacteria (Pseudomonas, Enterobacteriaceae and H2S-producing bacteria) were obtained with 1% CLE treatment than the control and SMS treated sample during entire storage of 12 days at 4 °C. When pulsed electric field (PEF) at varying specific energy densities (54 483 kJ/kg) and pulse numbers (200-600) was applied on PWS, PPO activity in cephalothorax was decreased as both parameters increased (p<0.05). Shrimp treated with PEF at highest level (PEF-T3) (483 kJ/kg, 600 pulses) had lower melanosis score than other samples, packaged in polystyrene trays and wrapped with shrink film, during 10 days of storage at 4 °C (p<0.05). Highest shear force values were noticed for the PEF-T3-treated sample at Day 10 (p<0.05). Microstructural gaping between shrimp muscle fibers was higher in PEF-T3. No protein degradation was observed for all samples. Lower total viable count (TVC) and psychrophilic bacterial count (PBC) in shrimp were obtained when PEF-T3 was implemented. After 10 days, higher sensory scores of PEF-T3-treated samples were attained, compared to others (p<0.05). The combined effect of PEF treatment applied on PWS before soaking in CLE at different concentrations (0.5 and 1%) for 30 min was investigated. Sample pre-treated with PEF and soaked with 1% CLE (PEF-1 CLE) showed lower melanosis score than that with 1.25% SMS treatment, PEF treated sample or those soaked in CLE without prior PEF and the control during storage of 10 days (p<0.05). PEF-1 CLE sample showed lower TVB, PV and TBARS, but high sensory scores than others (p<0.05). Lower increases in mesophile, psychrophile and spoilage bacterial counts were obtained in PEF-1 CLE. Chrysoeriol 6-C-glucoside-8-C-arabinopyranoside and veranisatin-C were found in PEF-1 CLE sample and were plausibly involved in keeping quality of shrimp. The effects of PEF and 1% CLE treatment on PWS packed under various modified atmospheres (MAP) including absolute N2, Ar or CO2 were studied. Lower melanosis score was evidenced in PEF pre-treated shrimp, followed by soaking in 1% CLE and packing under CO2-MAP (PEF-CLE-CO2) than the control and other treated samples during storage at 4 °C (p<0.05). PEF-CLE-CO2 showed lower pH, protein carbonyl content (PCC), TVB, peroxide value (PV) and TBARS, but exhibited higher likeness scores (p<0.05).. Spoilage and lactic acid bacterial (LAB) counts were less than 3 log CFU/g, which was lower than those of other samples at day 10 (p<0.05). Oxidation of fatty acids (EPA and DHA) was prevented in PEF-CLE-CO2 than the control and other treated samples (p<0.05). Volatile compounds in PEF-CLE-CO2 sample were negligible, compared to the control which was abundant in 3-methyl-1- butanol. The impact of high voltage cold atmospheric plasma (HVCAP) using dielectric barrier discharge (DBD) was implemented on PWS pre-soaked in 0.5 or 1% CLE solutions. Lower melanosis scores were found in the samples treated with 1% CLE and HVCAP in the presence of Ar and air (80:20) than the control and other samples throughout the storage of 15 days at 4 °C (p<0.05). Chemical quality changes in HVCAP treated PWS along with 1% CLE packaged in Ar and air MAP (CP-Ar/Air-1 CLE sample) were not significantly found at day 15. Microbiological and spoilage bacterial counts were less or equal to 5 log CFU/g meat in CP-Ar/Air-1 CLE sample, which were lower than the control and other treated samples at day 15 (p<0.05). CP- Ar/Air-1 CLE sample also exhibited higher likeness scores for all the tested attributes. Lipid and protein oxidation of HVCAP treated sample was prevented by 1% CLE, irrespective of gas composition. The effects of PEF pre-treated PWS were soaked in CLE solutions (1 or 2%), followed by HVCAP (under Ar + Air at 80:20) for 10 min, were elucidated. Least melanosis scores were attained in the samples pre-treated with PEF-T2 (800 pulses) and CLE (2%) prior to HVCAP (PEFT2-CLE2-Ar/Air-CP), compared to the control, during 18 days at 4 °C (p<0.05). The lowest microbial load and spoilage bacteria count (≤ 5 log CFU/g meat) were attained in PEFT2-CLE2-Ar/Air-CP sample (p<0.05). PEFT2-CLE2-Ar/Air-CP sample showed higher quality and likeness scores were noted in PEFT2-CLE2-Ar/Air-CP sample for all the attributes. Oxidation of polyunsaturated fatty acids and proteins was alleviated by CLE treatment. Effect of vacuum impregnation (VI) assisted penetration of CLE (1 or 2%) was studied at vacuum pressure of 5 kPa with various vacuum times (VT; 7.5-15 min) and restoration times (RT, 15-22.5 min) towards PEF treated PWS prior to MAP (Ar/Air; 80:20). Least melanosis scores were attained in samples pre-treated with PEF, VT-2 (15 min) and CLE (2%) (PEF-VI2-CLE2-MAP) than the control during 18 days, at 4 °C (p<0.05). Lower microbial load and spoilage bacteria counts were attained in PEF-VI2-CLE2-MAP sample (p<0.05). PEF-VI2-CLE2-MAP sample showed higher quality and likeness scores of all attributes when HVCAP was applied to treat PWS which were penetrated with CLE (1 or 2%) with the aid of VI (VT: 15, RT: 15 min) under Ar/Air (80:20) atmosphere for 10 min. Least melanosis scores and microbial load were attained in sample 2% CLE with the aid of PEF and VI and exposed to HVCAP (PEF-VI-CLE2-HVCAP) than the control during 18 days at 4 °C (p<0.05). This sample also showed lower lipid oxidation, pH, TVB and PCC than others (p<0.05). Higher likeness scores of all attributes were noted in aforementioned sample. Thus, shelf-life of PWS could be extended by the combination of non-thermal processes along with CLE up to 18 days.
Description: Thesis (Ph.D., Food Science and Technology)--Prince of Songkla University, 2020
URI: http://kb.psu.ac.th/psukb/handle/2016/19122
Appears in Collections:850 Thesis

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