Bos taurus, milk, pasteurized, homogenized, skimmed, fermented, spray-dried

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

other: expert statement supported by experimental data

Adequacy of study:

key study

Study period:

2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Version / remarks:

Regulation (EC) No 440/2008

Deviations:

no

Principles of method if other than guideline:

A determination of the water solubility of Yoghurt powder according to the OECD 105 protocol is not possible, because the test item seems to degrade during the test and therefore, its water solubility cannot be determined this way.

GLP compliance:

no

Type of method:

flask method

Specific details on test material used for the study:

Form: solid, powder
Lot No: 1:1:1 (weight) mixture of the three charges 107298, 106156 and 104439
Purity: 100%
Expiry date: Charge 107298: 2 May 2018 / Charge 106156: 10 October 2018 / Charge 104439: 24 May 2018
Storage: at room temperature, protected from light

Key result

Water solubility:

>= 1 - <= 10 g/L

Conc. based on:

test mat. (dissolved fraction)

Loading of aqueous phase:

10 g/L

Incubation duration:

ca. 24 h

Remarks on result:

other: based on the results of the preliminary test

Remarks:

test conducted at room temperature

Details on results:

Preliminary test
The approximate solubility is given as a function of the water volume under which complete dissolution of the sample occurs (see table in the next section). No dissolution of ca. 0.1 g test item was observed up to a volume of 100 mL using the setup described above. However, after 24 hours of stirring, the test item solution was clear and the test item seemed to be dissolved. Therefore, this preliminary test indicated a water solubility of 1 to 10 g/L.

Main test
Upon opening of the test assays for sampling purposes, the following observations were made:
- The colour of the test assay had changed from the initial milky white to a murky brown
- The initial neutral smell of the test solution had changed to a pervasive smell reminiscent of fermented milk

The same observations were made for test vessels two and three after stirring for 48 h and 72 h at about 30 °C, respectively, before 24 h of equilibration at about 20 °C with stirring.

These observations indicate that the test item had begun to degrade since the start of the test. This hypothesis seems very likely considering that the test item should be ready bioavailable based on its origin (this was confirmed in the ready biodegradation study, see cross-ref.) and contains viable bacterial cells according to sponsor information. Furthermore, the incubation temperatures of this test, especially the initial saturation at about 30 °C are ideal for bacterial growth. Due to these observations, further testing was stopped.

Testing scheme to determine the approximate water solubility in the preliminary test:

mL of water for 0.1 g test item	0.1	0.5	1	2	10	100	>100
Approximate solubility in g/L	>1000	1000 to 200	200 to 100	100 to 50	50 to 10	10 to 1	<1

Conclusions:

A determination of the water solubility of Yoghurt powder (EC 917-734-0) according to the OECD 105 protocol is not possible, because the test item seems to degrade during the test and therefore, its water solubility cannot be determined this way.
Based on the results of the preliminary test, where no degradation was apparent (test lasted only for about 24 hours and was conducted at room temperature), the water solubility can be given as 1 to 10 g/L at room temperature.

Executive summary:

It was the aim of this expert statement to assess the water solubility of Yoghurt powder (EC 917-734-0) according to TG OECD 105.

The preliminary test according to the guideline showed that the test item could be dissolved in 100 mL of ultra-pure water after about 24 hours of stirring at room temperature.

In the definitive test, several test vessels containing ultra-pure water mixed with test item in great excess (initial amount of test item about 50 g per liter water), were incubated and stirred for different periods of time at about 30°C (saturation phase), and then transferred to about 20°C for 24 h (equilibration phase).

Upon opening of the test assays for sampling purposes, a color change from milky white to murky brown was apparent as well as a pervasive smell reminiscent of fermenting milk, which was not the case at the start of the test. Both observations, which were made for three different test assays, are indicative of a test item degradation. This hypothesis seems very likely considering that the test item should be ready bioavailable based on its origin and contains viable bacterial cells according to sponsor information. Furthermore, the incubation temperatures of this test, especially the initial saturation at about 30°C are ideal for bacterial growth. Due to these observations, further testing was stopped.

A determination of the water solubility of Yoghurt powder according to the OECD 105 protocol is not possible, because the test item seems to degrade during the test and therefore, its water solubility cannot be determined this way.

Based on the results of the preliminary test, where no degradation was apparent (test lasted only for about 24 hours and was conducted at room temperature), the water solubility can be given as 1 to 10 g/L at room temperature.

Description of key information

It was the aim of this expert statement to assess the water solubility of Yoghurt powder (EC 917-734-0) according to TG OECD 105. A determination of the water solubility according to the OECD 105 protocol is not possible, because the test item seems to degrade during the test and therefore, its water solubility cannot be determined this way.

Based on the results of the preliminary test, where no degradation was apparent (test lasted only for about 24 hours and was conducted at room temperature), the water solubility can be given as 1 to 10 g/L at room temperature.

Key value for chemical safety assessment

Water solubility:

10 g/L

at the temperature of:

25 °C

Additional information

Based on the results of the preliminary test, where no degradation was apparent (test lasted only for about 24 hours and was conducted at room temperature), the water solubility can be given as 1 to 10 g/L at room temperature.