AU2021104594A4

AU2021104594A4 - Methods for improving lycopene release rate and lycopene bioavailability in tomatoes

Info

Publication number: AU2021104594A4
Application number: AU2021104594A
Authority: AU
Inventors: Fuguo LIU; Xuebo LIU; Yuyan LU; Cuicui MA
Original assignee: Northwest A&F University
Current assignee: Northwest A&F University
Priority date: 2021-07-27
Filing date: 2021-07-27
Publication date: 2021-09-23
Anticipated expiration: 2029-07-27

Abstract

The present invention discloses a method for improving release rate and bioavailability of lycopene in tomatoes, which is belonging to the technical field of functional food processing. The method is to increase the release rate of lycopene by fermenting tomato juice, then mixing the resulting fermentation solution with oil and shearing as well as homogenizing the resulting mixture, finally tomato juice with high nutritional value is obtained. The preparation method is simple and convenient in operation, no organic reagent is added, and this method can significantly increase the release rate and bioavailability of lycopene from tomato juice. It is suitable for large-scale production and processing of tomato products.

Description

Methods for improving lycopene release rate and lycopene bioavailability in

tomatoes

TECHNICAL FIELD

The present invention belongs to the technical field of functional food processing,

and in particular relates to a method for improving the bioavailability of lycopene in

tomato juice.

BACKGROUND

Lycopene, a type of carotenoid, has antioxidant, immunomodulatory and

anticancer effects, and it is effective in preventing breast cancer, prostate cancer,

cardiovascular disease and other diseases. Lycopene in tomato plant cells is in a bound

or free state. Lycopene in the bound state is protected by cell walls and is difficult to be

absorbed and utilized by the body when eating. Through brewer's yeast fermentation,

the free state of lycopene is significantly increased so that it can be better absorbed and

utilized by the body.

However, the free state of lycopene lacks the protection of tomato plant cell walls,

and it is more susceptible to loss by external environmental factors, especially during

the mechanical processing and storage of juice. So it is important to improve the

stability of lycopene by some means, thus increasing the bioavailability of lycopene in

the product.

The emulsification of oils can enable the lycopene to be absorbed effectively by

the human body, and at the same time, the loss of the free state by external

environmental factors can be avoided, so it is important to use the emulsification of oils to reduce the loss of the free state of lycopene and to improve the utilization of lycopene by the human body.

SUMMARY

The purpose of the present invention is to provide a method for increasing the

release rate and bioavailability of lycopene in tomatoes, by means of the following

technical solutions:

A method for improving the release rate and bioavailability of lycopene in

tomatoes: Fermenting tomato juice to obtain a fermentation treatment solution, then

mixing the fermentation solution with plant oil to obtain a mixture, which is then

sheared and homogenized.

The fermentation solution is obtained by dispersing tomato juice and yeast in

deionized water. Further, after the tomato juice and yeast are dispersed in deionized

water and stirred to dissolve, a fixed fermentation time and fermentation temperature is

maintained to obtain the best fermentation results.

The yeast mentioned is brewer's yeast and the oil is a type of plant oil (peanut oil,

olive oil, corn oil, canola oil, etc.).

The tomato juice is obtained by blanching the tomatoes, removing the skin and

seeds, squeezing the juice and filtering through a 40-80 mesh sieve with two layers of

medical gauze. The hot blanching temperature is 80 ~ 90 °C, hot blanching time is 2 ~

min; the juice was beat by juicer more than 1min.

The volume fraction of yeast in the fermentation broth is 3-5% and the mass

fraction of the oil is 1-3 % .

The tomato juice fermentation conditions described are: temperature 20-30°C and

time 24~48 h.

The conditions of high shear mixing described are: speed 2000-5000 rpm and

time 5-15 min.

Using the method of the invention, the lycopene release from tomato juice could

reach 45.13 mg/100g, and the highest bioavailability enhancement could reach 81.24%.

The beneficial effects of the present invention are:

(a) The present invention uses yeast fermentation to disrupt the natural cell wall

barrier of tomatoes, resulting in an effective enhancement of the lycopene release rate:

the present invention uses oil as an emulsifier, which protects free lycopene, promotes

absorption in the body and effectively improves the bioavailability of tomato juice.

(b) Compared to current method using homogenization for processing tomato

juice to enhance lycopene release, the release rate of lycopene in the present invention

is higher and the bioavailability is more significantly enhanced. The invention has the

advantages of low energy consumption, simple preparation condition, high efficiency

and mild conditions, and is suitable for the mass production of industrial products such

as tomato drinks and health products.

BRIEF DESCRIPTION OF THE FIGURES

(a) Figure 1 shows the release rate of lycopene from the fermentation solution

resulting from the single factor test of temperature, time and incubation volume

performed in Example 1. Different letters indicate significant differences (p < 0.05)

(b) Figure 2 shows the response surface plot of lycopene content against

fermentation temperature, fermentation time, and yeast incubation quantity., for the

optimization of fermentation condition to obtain the best lycopene release efficiency.

(c) Figure 3 shows the bioavailability of lycopene in tomato juice products

obtained from unfermented, fermented, unfermented-emulsified, and

fermented-emulsified groups. E: Emulsified; Different superscript letters show

significant differences (p < 0.05) between samples.

DESCRIPTION OF THE INVENTION

The present invention provides a method for increasing the release rate and

bioavailability of lycopene in tomatoes, which is further described below in

conjunction with the examples and accompanying figures.

The tomatoes used in this invention are all the same batch of commercially

available high-quality tomatoes with clean and unpolluted surfaces, red color and

uniform size, provided by local supermarkets.

The tomato juice is fermented to get the fermented solution, and then the

fermented solution is mixed with vegetable oil to get the mixed solution, which is

sheared and homogenized to get the final tomato juice. Tomato juice sample without

yeast and oil was used as the blank control 1, specifically: fresh tomatoes were hot

blanched at 80-90°C for 5 min to remove the skin and stems, pulped for 2 min with a

juicer and then filtered through 40 mesh sieve and two layers of medical gauze to

remove the seeds so that the tomato juice was obtained.

Tomato juice sample without yeast but treated with oil emulsification was used as

control 2, as follows: the tomato juice obtained from the blank control 1 was mixed

with oil in high shear under the following conditions: rotational speed of 3500 rpm,

time of 10 min and oil addition of 2% mass fraction to obtain the emulsified tomato

juice.

Example 1

Lycopene release from tomato juice was enhanced by fermentation treatment of

tomato juice with brewer's yeast S. cerevisiaeATCC 9763 according to the following

method:

(1) Fresh tomatoes were blanched at 80-90°C for 5 min to remove the skin and

stems, pulped for 2 min with a juicer and then filtered through a 40-mesh sieve and two

layers of medical gauze to remove the seeds so as to obtain tomato juice.

(2) The yeast brewer's yeast S. cerevisiaeATCC 9763 was maintained on Peptone

Dextrose Agar slants at 4 °C. Active cultures were prepared by transferring a cell loop

from the agar slant into a test tube containing 5 mL of liquid Sabouraud medium. The

culture was then incubated overnight at 30 °C with gentle agitation to go through the

logarithmic growth phase for 12-16 h, the optical density at 600 nm (OD600) of the

ATCC 9763 was adjusted to 1.0 cm-' to ensure the yeast was in a stable period of

fermentation.

(3) The tomato juice obtained from step (1) was fermented by brewer's yeast

ATCC 9763 obtained from step (2), one-way tests of temperature, time and incubation

volume were performed to determine the optimal level of each variable.

(4) Firstly, fixed fermentation time of 12 h with a yeast incubation of6% (v/v), the

effect of fermentation temperature (15, 20, 25, 30, 35 and 40°C) on lycopene content

was analyzed. Then the effect of fermentation time (0, 12, 24, 36, 48, 60 and 72 h) on

lycopene content were analyzed using a fixed fermentation temperature of 25°C and a

yeast incubation volume of 6% (v/v). Finally, the effect of yeast culture volume (3, 4, 5,

6, 7, and 8% (v/v)) on lycopene content was studied at a fixed fermentation temperature

of 25°C and a fermentation time of 12 h.

(5) Through the single factor test of step (4), using the commercial software

Design Expert 8.0, the optimal fermentation conditions are determined through

response surface design: 30 °C, 36 h and 4.9% (v/v) inoculum.

(6) After fermenting the tomato juice with the optimal fermentation conditions in

step (5), lycopene was detected in the samples using high-performance liquid

chromatography. The chromatographic column is YMCTMC30 (150mmx4.6mm,

pm), the mobile phase is 90% methanol and 10% MTBE, the flow rate is 0.8 mL/min,

the injection volume is 20 L to 80 L, and the detection wavelength is 450 nm and 470

nm. According to the Lambert-Beer law, the lycopene content is calculated by the

following formula.

x = (A x y)/(A1 x 100000) (1)

Where: x is the content of lycopene contained in the sample (mg/100 g); y is the

volume of the sample solution (mL); A is the peak area of the corresponding lycopene

in the sample (mV-s); Al is the absorption coefficient, that is, the theoretical absorption value of 1% (V/V) content of solute in a cuvette with 1 cm optical path length. The value used when calculating the lycopene content isc=3400 (474 nm).

In the actual experiment, the content of lycopene was 45.1 mg/100 g. Compared

with the unfermented tomato juice, the release rate of lycopene was greatly improved.

Example 2 The tomato juice was fermented by Saccharomyces cerevisiaeATCC

9763 and the lycopene content in the tomato juice was increased by emulsifying peanut

oil according to the following methods:

(1) The fermented tomato juice obtained in Example 1 were mixed with a mass

fraction of 2% peanut oil at a rotation speed of 3500 rpm for 10 min under high shear to

obtain an emulsified sample.

(2) The bioavailability of lycopene in emulsified samples from unfermented,

fermented, unfermented-emulsified, and fermented-emulsified groups was determined

by simulating the in vitro oral-gastric-small intestine digestion system according to the

following method.

Before starting each digestion stage, 2.5 g of all tomato juice samples obtained by

the above method were mixed with 10 mL of PBS buffer in a 50 mL centrifuge tube.

Simulated oral digestion: Added artificially extracted saliva containing a-amylase

to the centrifuge tube to a concentration of 1.11 units/mL in the mixed solution. The

centrifuge tubes were incubated in a constant temperature shaker at 37 °C for 10 min at

120 rpm. The above solution was the first step digestive solution.

Simulated gastric digestion: first configured the simulated gastric juice, dissolved

the appropriate amount of pepsin in 1 M HCl, added it to the treatment solution in the first step solution, adjusted the concentration of pepsin to 10 units/mL, and adjusted the pH to 2.5. The mixture was configured with PBS buffer to 40 mL and then incubated in a constant temperature shaker at 37 °C for 1 h at 120 rpm. The pH was adjusted to 6.0 with 1 M NaHCO3 after incubation. The above solution was the second step digestive solution.

Simulate intestinal digestion: first dissolved appropriate amounts of porcine bile

extract, porcine pancreatic juice and lipase in 100 mM NaHCO3, added them to the

second digestive solution and adjusted the concentration of porcine bile solution to 1.6

units/mL, trypsin solution concentration to 40 units/mL and lipase solution

concentration to 5 units/mL, and adjusted pH to 6.5 with PBS buffer, volume to 50 mL,

then incubate at 37°C for 2h. The above solution was the third step digestive solution.

Took 15 mL of third step digestive juice, centrifuged at 40,000 x g for 40 min at 4 °C,

and the supernatant represented the "micelle" fraction formed during the digestion. The

Lycopene Bioaccessibility (LBA) of lycopene was calculated using the following

equation:

LBA (%) = Xmice 100 Original digestive fluid

Where C micee is the concentration of lycopene in the micelle fraction ([g/mL);

Coriginal digestive fuid is the concentration of total lycopene in the original digest ([g/mL).

Lycopene bioavailability in different tomato juice samples is shown in Figure 3.

The bioavailability of lycopene in the four groups of tomato juice were: Unfermented

group 8 .5 % < fermented group 11.4% < unfermented-emulsified group 1 3 .6 % < fermented-emulsified group22.7%. It can be seen that fermentation and emulsification treatments can substantially increase the bioavailability of lycopene in tomato juice.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A method for improving the release rate and bioavailability of lycopene in

tomatoes, characterized in that the tomato juice is fermented to obtain the fermentation

solution, and then the fermentation solution is mixed with oil to obtain a mixture, which

is sheared and homogenized;

The processing conditions described were all carried out in a solution environment

of deionized water.

2. The method according to claim 1, characterized in that the volume fraction of

yeast in the fermentation broth is 3-5% and the mass fraction of oil is 1-3%.

3. The method according to claim 1, characterized in:

The yeast is brewer's yeast.

The oil is one of plant oil (peanut oil, olive oil, corn oil, canola oil, etc.).

4. The method according to claim 1, characterized in that the tomato juice is

obtained by hot blanching and washing the tomatoes to remove the skin and seeds,

squeezing the juice and filtering it through a 40-80 mesh sieve with two layers of

medical gauze; the hot blanching temperature is 80 ~ 90 °C, hot blanching time is 2 ~

min and the juicing machine adopts a juicer to beat the pulp for more than 1 min.

5. The method according to claim 1, characterized in that the fermentation

conditions of the tomato juice belongs to: temperature 20-30 °C, time 24~48 h.

6. The method according to claim 1, characterized in that the conditions of the

high shear mixing are: rotational speed 2000-5000 rpm and time 5~15 min.