Hoá Phân Tích

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Analytical Approach

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06 · Phạm Bùi Nam AnhID : 207720201003

05 · Nguyễn Tấn Anh KhoaID : 207720201018

04 · Nguyễn Thành Đạt ID : 207720201007

03 · Nguyễn Minh KhôiID : 207720201020

02 · Đào Phương Vy ID : 207720201045

01 · Trần Ngọc Bảo NgânID : 207720201025

GROUP MEMBER

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05 · Propose a solution

04 · Analyze the experimental data

03 · Conduct an experiment

02 · Design the experimental procedure

01 · Identify the problem

index

• Enoki mushrooms (Flammulina velutipes) is a saprophytic heterotrophic fungus belonging to the genus Chrysalis and is widely distributed in nature..

• Carboxymethyl chitosan is a water-soluble chemical modification product of chitosan and has antibacterial activity and good coating forming ability.

• Glutathione has potent antioxidant activity and can suppress browning.

• Owing to their antibacterial and antioxidant activities, carboxymethyl chitosan-based coatings incorporated with glutathione could extend the shelf life of enoki mushrooms.

1. Identify the problem

Sampling

Browning degree

Soluble solids

Weight loss

Respiratory rate

Bacterial determination

2. Design the experimental procedure

Materials

• Enoki mushrooms: harvested ->framed ->bagged ->storage at 2–4 °C and 85% humidity for 24 h. On the 2nd day, qualified enoki mushrooms were selected for further use.

• Carboxymethyl chitosan: deacetylation degree of 93.5% and a molecular weight of 41 × 104.

3. Conduct an experiment

Treatment of enoki mushrooms

• Dipping solutions: Purified water (control), 1% carboxymethyl chitosan (Treatment-1) and 1% carboxymethyl chitosan + 0.2% glutathione (Treatment-2)
• 216 plants of enoki mushrooms were selected and randomly divided into two treatment groups (Treatment-1 and -2)
• The samples were soaked in the dipping solutions for 20 min at 3 ± 1 °C ->removed
• ->drained at room temperature, and placed in baskets (three plants in one basket)
• PE bags with a thickness of 0.5 mm were poked with holes and used to cover the baskets.
• The enoki mushrooms were stored in a cold place at 3 ± 1 °C

3.Conduct an experiment

a. Total viable countb. Respiratory ratec. Weight lossd. Soluble solidse. Browning degreef. Sensory evaluation

4. Analyze the experimental data

Fig. 1. Effect of carboxymethyl chitosan-based coatings on total viable count (TVC) of enoki mushrooms (Flammulina velutipes) during refrigeration. Bars represent the standard deviation (n = 6).

a. Total viable count

- There were no discernible variations in TVCs between the two treatment groups, indicating that glutathione had no antibacterial effect on enoki mushrooms. → Glutathione had no antibacterial effect on enoki mushrooms. - The TVC of the control group steadily increased (P < 0.05) during refrigeration, whereas that of the two treatment groups decreased after 2 days of refrigeration and then only slightly increased during the remaining period (Fig. 1). → This finding could be attributed to the antibacterial activity of carboxymethyl chitosan (Olanipekun et al., 2021).

4. Analyze the experimental data

Fig. 2. Effect of carboxymethyl chitosan-based coatings on respiratory rate of enoki mushrooms (Flammulina velutipes) during refrigeration. Bars represent the standard deviation (n = 6).

- The respiration rate of all groups increased during the whole cold storage. However, the respiration rates of the treatment groups were lower than those of the control group. Moreover, the respiration rates of Treatment-2 group were lower than those of Treatment-1 group. -> Carboxymethyl chitosan and glutathione decreased the respiration rates of enoki mushrooms

4. Analyze the experimental data

b. Respiratory rate

Fig. 3. Effect of carboxymethyl chitosan-based coatings on weight loss of enoki mushrooms (Flammulina velutipes) during refrigeration. Bars represent the standard deviation (n = 6).

- The weight loss of enoki mushrooms increased steadily during cold storage. According to Wu (2013), glutathione has strong reducing properties for ferric iron and ferrous iron ratio as well as oxygen partial pressure, which further reduced the respiration rates of enoki mushrooms. -> Glutathione further decreased the respiration rate and therefore inhibited the weight loss of enoki mushrooms.

4. Analyze the experimental data

c. WEIGHt loss

d. Soluble solids

Fig. 4. Effect of carboxymethyl chitosan-based coatings on soluble solids of enoki mushrooms (Flammulina velutipes) during refrigeration. Bars represent the standard deviation (n = 6).

- The soluble solid contents of the two treatment groups were generally higher than that of the control group after 4 days of refrigeration. -> Coatings made of carboxymethyl chitosan reduced the rate of respiration during refrigeration, which in turn reduced the consumption of soluble solids.

4. Analyze the experimental data

Fig. 5. Effect of carboxymethyl chitosan-based coatings on browning degree of enoki mushrooms (Flammulina velutipes) during refrigeration. Bars represent the standard deviation (n = 6).

- After 12 days of refrigeration, the browning degree of Treatment-2 group was lower than that of Treatment-1 and control groups. -> This finding could also be ascribed to the ability of glutathione to suppress enzymatic browning

e. Browning degree

4. Analyze the experimental data

Fig. 6. Effect of carboxymethyl chitosan-based coatings on overall likeness of enoki mushrooms (Flammulina velutipes) during refrigeration. Values are means of three replicates. Vertical bars represent standard deviation.

- After 12 days of chilling, all groups' overall likeness ratings gradually fell. The Treatment-2 group's overall likeness score remained higher than the lowest permissible value after 12 days of refrigeration. -> Therefore, enoki mushrooms can have their shelf life increased by at least 6 days by treatment with coatings made of carboxymethyl chitosan.

f. Sensory evaluation

4. Analyze the experimental data

As compared to the control group, enoki mushrooms treated with carboxymethyl chitosan-based coatings significantly reduced the physiological and sensory quality alterations and increased shelf life by at least 6 days. So, enoki mushrooms can be preserved using this potential method.

5.Propose a solution

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