Related Experiment Videos
[Proteo-polysaccharidic turbidity in depectinized raspberry juice]
Annales De La Nutrition Et De L'Alimentation
|January 1, 1978
Summary
Refrigerated red raspberry juice develops turbidity due to cold-induced flocculation of large nitrogenous molecules with polysaccharides. This process involves proteins and manno-glucans, impacting juice stability.
Area of Science:
- Food Science
- Biochemistry
- Analytical Chemistry
Background:
- Turbidity in depectinized red raspberry juice occurs under refrigeration.
- This phenomenon is linked to cold and acidic pH conditions.
Purpose of the Study:
- To analyze the chemical and physical properties of the turbidity in red raspberry juice.
- To identify the molecular components responsible for the observed turbidity.
Main Methods:
- Chemical analysis included total sugar, galacturonic acid, and total nitrogen determination.
- Physical analysis involved atomic absorption spectroscopy for mineral content.
- Chromatographic techniques (HPLC, GPC, DEAE-cellulose) were used for separation and molecular weight determination.
Main Results:
- Turbidity results from the flocculation of large nitrogenous molecules (proteins) with polysaccharides (manno-glucans).
- The depectinizing preparation had a high molecular weight (>150,000), while the polysaccharides ranged from 1,000 to 10,000.
- The manno-glucan entity's origin is uncertain, possibly from raspberry pectic substances or Aspergillus niger.
Conclusions:
- Cold and acidic pH trigger flocculation between proteins and polysaccharides, causing turbidity in raspberry juice.
- Understanding these interactions is crucial for maintaining juice stability and quality.