Table 11 The results of constant, linear regression coefficients of variables for the ultrasound-assisted extraction of astaxanthin with different solvents from P. maeoticus Gammarus

From: Green astaxanthin extraction using microwave and ultrasound pretreatments

Factor

Organic solvent

Vegetable oil

Ionic microemulsion

Coefficient estimate

df

Standard error

95% CI low

95% CI high

Coefficient estimate

df

Standard error

95% CI low

95% CI high

Coefficient estimate

df

Standard error

95% CI low

95% CI high

Total carotenoid content

Intercept

19.45

1

0.8450

17.66

21.24

3.90

1

0.2778

3.31

4.49

49.14

1

1.52

45.91

52.37

A.Ratio

−7.58

1

1.20

−10.11

−5.05

−0.5407

1

0.3928

−1.37

0.2920

−12.11

1

2.16

−16.68

−7.54

B.Power

−0.4221

1

1.20

−2.96

2.11

0.9274

1

0.3928

0.0947

1.76

−0.5760

1

2.16

−5.15

3.99

C.Time

0.9556

1

1.20

−1.58

3.49

1.20

1

0.3928

0.3648

2.03

4.46

1

2.16

−0.1087

9.03

0.7193

0.5116

0.6917

Adjusted R²

0.6667

0.4201

0.6339

Predicted R²

0.5637

0.2024

0.3631

Astaxanthin concentration

Intercept

15.68

1

0.7545

14.08

17.27

3.12

1

0.2671

2.55

3.69

45.28

1

1.41

42.29

48.28

A.Ratio

−6.94

1

1.07

−9.20

−4.68

−0.4922

1

0.3777

−1.29

0.3085

−9.67

1

2.00

−13.91

−5.43

B.Power

−0.8398

1

1.07

−3.10

1.42

0.6094

1

0.3777

−0.1913

1.41

−1.08

1

2.00

−5.32

3.15

C.Time

−0.0048

1

1.07

−2.27

2.26

1.28

1

0.3777

0.4817

2.08

3.50

1

2.00

−0.7358

7.74

0.7286

0.4973

0.6256

Adjusted R²

0.6778

0.4031

0.5554

Predicted R²

0.5385

0.1961

0.2708

Astaxanthin recovery yield

Intercept

78.86

1

0.8144

77.14

17.27

76.93

1

2.84

70.90

82.96

92.31

1

0.6999

90.83

93.80

A.Ratio

−5.13

1

1.15

−7.58

−4.68

0.2010

1

4.02

−8.33

8.73

2.37

1

0.9898

0.2687

4.47

B.Power

−1.97

1

1.15

−4.41

0.4754

−2.77

1

4.02

−11.29

5.76

−1.33

1

0.9898

−3.43

0.7663

C.Time

−2.56

1

1.15

−5.01

−0.1236

6.70

1

4.02

−1.83

15.23

−0.3340

1

0.9898

−2.43

1.76

0.6343

0.1688

0.3233

Adjusted R²

0.5657

0.0129

0.1964

Predicted R²

0.3599

−0.4327

−0.0460