Starter Cultures and Fermented Milk Products

Lesson 15. COMPOSITION OF SYNTHETIC AND BACTERIAL DISTILLATES, PRODUCTION AND APPLICATION

Module 10. Starter distillates

Lesson 15

COMPOSITION OF SYNTHETIC AND BACTERIAL DISTILLATES, PRODUCTION AND APPLICATION

15.1 Introduction

Starter distillate is made from fermentation of skim milk or non fat dry milk by several bacteria. Starter distillate is considered as GRAS (generally recognized as safe) by FDA and regulated under code of food regulation title 21part 184.1848.

According to FDA, starter distillate or butter starter distillate is a steam distillate of the culture of any or all of the following species of bacteria grown on amedium consisting of skim milk usually fortified with 0.1% citric acid: Lactococcus lactis ssp .lactis, L. lactis ssp .cremoris, and L.lactis ssp . lactis biovar diacetylactis, Leuconostoc citrovorum, and L.dextranicum. The ingredient contains more than 98% water, and reminder is a mixture of butter like flavouring organic compounds. Besides diacetyl, starter distillate contains minor amounts of acetaldehyde, ethyl formate, ethylacetate, acetone, ethyl alcohol, 2-butanone, acetic acid and acetoin.

These all-natural butter flavor systems possess a smooth, rich, fresh butter character, making them ideal for applications in numerous food formulations. Especially popular is the usage in the manufacture of:

• Dairy products,

• Baked goods,

• Confections,

• Salad dressings,

• Snack foods,

• Marinades, and as well as imitation dairy flavors

Further they are excellent natural replacements for synthetic diacetyl.

15.2 Composition of Synthetic and Bacterial Distillates

Starter Distillates are derived from selective lactic culture fermentation of milk and further purified by steam distillation. These Liquid Butter flavours have a standard identity as described in the food additive regulations of 21 CFR 184.1848. They are Generally Recognized as Safe (GRAS) ingredients and can be labeled as “natural flavours”.

15.3 Production and Application

15.3.1 Bacterial distillates

Natural butter aroma distillate can be prepared by growing the mixed cultures consisting of Lactococcus lactis ssplactis, Lactococcus lactis ssp cremoris and Lactococcus lactis ssp lactisbiovar diacetylactis in the culture medium containing skim milk or whey as substrate. The cultures will produce substantial amount of α-acetolactic acid. The bacterial culture medium having a substantial amount of α-acetolacticacid is acidified to a pH of about 3.5 . water vapour distillation is carried out effectively in the presence of oxygen to convert the α-acetolactic acid to diacetyl and to distill off approximately 5-15% of the bacterial culture medium. The resultant distillate has a diacetyl content ranging from 1369- 2666mg/kg.

15.3.2 Synthetic distillates

The synthetic distillates contains edible fats which replaces souring by starter cultures

Advantages

1. Results in yield of sweet buttermilk.

2. Greater freedom when optimizing the temperature treatment of cream before churning.

3. Yields more consistent product quality in particular as regards odour and flavour.

Disadvantage

1. Addition of pure synthetically prepared diacetyl gives a harsh undesirable taste of diacetyl.

A balanced butter flavour can be obtained by adding other important aroma substances, such as acetic acid, dimethyl sulphide, acetaldehyde and certain lactones.