Dairy products and milk-based food ingredients - Natural Food Additives, Ingredients and Flavourings - page 437

from Penicillium roqueforti , Penicillium camemberti , Aspergillus niger and
Candida rugosa (amongst others) are active in the hydrolysis of triacylglycerols
to fatty acids. The proteolytic enzymes yield low molecular weight peptides and
amino acids which provide savoury and umami fl avours, while the lipolytic
enzymes liberate short, medium and long chain free fatty acids (FFAs). Short
chain (C2-C6) FFAs contribute cheesy fl avours, while medium chain (C8-C14)
FFAs give buttery notes. Long chain FFAs (>C16) can give a soapy mouthfeel.
Incubation to achieve protein and fat hydrolysis is undertaken in the range
40-50°C for between 10 and 50 hours, depending on the product, the activity of
the enzyme and the degree of fl avour development required. When the required
level of hydrolysis has been achieved, EMC is heat-treated at around 90°C to
denature the enzymes and cooled to be packaged as a paste. Alternatively it may
be spray-dried to give a powdered ingredient that can be dusted onto or incorporated
into products. As a paste or a powder it is used as an ingredient in food products
(e.g. snack foods, savoury baked products, soups and sauces) as well as a fl avour
booster in processed cheese.

17.4.5 Milkfat products
Anhydrous milkfat (AMF), butteroil and fractionated milkfats are used widely as
food ingredients. The minimum fat content of AMF is 99.8% and of butteroil is
99.3%. AMF is made from fresh cream or butter, whereas butteroil may be made
from cream or butter of different ages. AMF is frequently made from butter that is
not expected to sell within the time required to maintain acceptable quality. Sweet
cream, unsalted butter is normally used, but salted butter and cultured butter are
also suitable raw materials. During the processing of AMF, butter is melted to
60-65°C by indirect heat transfer and held at this temperature for 20-30 minutes
to allow milk protein aggregation. The oil may then be 'neutralised' and 'polished'.
Neutralisation may be necessary to remove free fatty acids (FFAs) which will
affect the fl avour of the AMF. Sodium hydroxide (NaOH) is added to the oil at a
level required to saponify the FFAs. The addition of 20-30% water for polishing
allows the solution of water-soluble substances (proteins and soap). The oil-water
mix is then passed through a centrifugal separator which concentrates the fat to
99.5% and removes the non-fat solids and much of the added water. The milkfat
is then taken to 90-95°C before passing through a vacuum fl ash-vessel, which
serves to remove traces of water and cool the fat to 37-40°C ready for packaging
(at lower temperatures the high melting point triacylglycerols crystallise and
cause problems with packing operations).
The manufacture of AMF from cream is a little different in that the milkfat
emulsion must fi rst be destabilised through phase inversion, whereas this has
already happened when butter is used. Butteroil manufacture uses essentially the
same process as AMF. Both AMF and butteroil are packaged for retail sale and
industrial use in containers varying in size from 1 kg to 200 kg. The containers are
usually gas fl ushed with nitrogen to remove air and prevent lipid oxidation during
storage.

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