Mention chicken broth or beef stock, and the mind conjures
up comforting thoughts of crisp autumn days, warm woolen
jackets, family gatherings and savory aromas wafting from
mother's kitchen as meaty bones or giblets stew in the stock
pot. This visceral connection is our mental GPS to memories,
when the senses are flooded to the brim and overflowing with
feelings of vitality and belonging.
These feelings are so linked to our primitive nature that
they are a part of our literary lexicon as we "take stock" of
our blessings, read about "chicken soup for the soul" and sip
broth soups to fend away the common cold (Ohry and Tsafrir,
1999). With such a strong emotional connection, it's no wonder
that prepared foods commonly feature broth as a prominent
ingredient. And it's no surprise that some petfood
manufacturers, understanding this connection, are using broth
in producing foods for dogs and cats.
While it has all these wonderful attributes, let's be clear
that broth's place in petfood is virtually the same as that for
human foods. It's more of an emotional connection for the
purchaser than a nutritional or taste driver for the pet.
In petfood, the most common application has been in canned
foods in lieu of the "water sufficient for processing" or in
specialty gravies and sauces. Despite conventional wisdom, in
these formats broth doesn't impart a measurable impact to the
overall palatability.
Further, it has only minimal, if any, impact on the aroma of
most petfoods. This is probably because these foods have pretty
strong and distinctive aromas already and any beneficial aroma
from the broth simply gets overwhelmed. On the other hand, in
more subtle offerings such as fortified water for dogs, there
may be some measurable palatability benefit to broth/stock
additions.
Since the solids in broth are so small, any beneficial
nutrient contributions are overwhelmed by the rest of the
ingredients. However, broth does contribute an interesting
array of water soluble proteins, nucleic acids, sugars, salts
and fats from muscle, bone and marrow of the simmered meats and
trimmings. During production, most of the fat is removed (or
rendered), but volatile short chain fatty acids and alcohols
contribute to the aromas. The soluble and gelatinous proteins
from cartilage contribute to the viscosity of the broth and to
the taste and mouth-feel due to the high content of glutamic
acid in collagen.
Another contributing factor are 5' nucleotides from the
rupture of the muscle cell nucleus (e.g.,
cytidine-5'-monophosphate, uridine-5', guanosine-5, inosine-5'
and adenosine-5'-monophosphate). These compounds are associated
with the mouth-feel/taste sensation of umamia savory sensory
note most commonly associated with the flavor of soy sauce.
Broth, stock, au jus, essence, bouillon, consommé and
extract are all synonyms of this watery meat derivative. The
actual definition for petfood allows for only the name "broth
or stock." These names are derived from the US Department of
Agriculture definition for beef stock, which sets a minimum
amount of solids, rather than chicken broth, which does
not.
In these formats broth doesn't impart a measurable impact to the overall palatability.The AAFCO definition for stock/broth reads:
" is obtained by cooking mammalian or poultry bones, parts
and/or muscle tissue. The crude protein content of stock/broth
must be no less than 90% on a dry matter basis. In order for
the stock/broth to be labeled as such, the moisture to crude
protein ratio must not exceed 135:1 (135 parts water to 1 part
crude protein). The product must bear a name descriptive of its
kind, composition or origin, such as, but not limited to, meat,
beef, pork, poultry, chicken, turkey: and may be called either
stock or broth."
While compliance with this definition may seem convoluted,
most of the broth/stock suppliers are able to unravel how this
directly impacts a petfood formula and can provide directions
and amounts to meet a specific need.
At home, broth in its simplest incarnation is meat parts
simmered or roasted with water, onion, celery and other
seasonings; then the liquid is strained from the larger
particles for incorporation into recipes. Generally, commercial
broth is much simpler with no vegetables or seasonings added;
the idea is that the cook will add his or her own.
An example of a middle-of-the-road commercial chicken stock
process starts with layers or heavy hens cooked in large
kettles for two to three hours at 190-200 degrees Fahrenheit
until the meat is tender. A much more subtly flavored
commercial chicken broth is produced from ground meats (no
bones) cooked for a short time. At the other extreme, some beef
stocks are derived from bones cooked for six to 12 hours under
high pressure and temperature. In general the more intense
processes give higher yields and stronger flavors.
In the grocery store, broth is sold canned or in dried cubes
as bouillon. These preparations may be high in sodium and other
additives. Commercial broth used in prepared foods is most
commonly available as frozen blocks or a spray-dried powder.
The frozen products are sold as 16% and 32% solids.
Spray-dried products often need carriers, such as
maltodextrins, to help achieve the right drying conditions and
final product consistency. Frozen broth must be maintained in
this state until use or it will spoil. Dry broth is more
shelf-stable but must be held in a dry environment as it can be
hygroscopic.
The flavor and aroma of broth is often best right at the
time of productionfresh. The volatile flavor (aroma) notes are
affected by freezing, packaging, drying and storage time. For
the few petfood applications that rely upon such subtleties,
production dates and turnover will need to be monitored
closely.
Broth is produced commercially for the human prepared foods
and home use market. No pet or "inedible" specific stock is
commonly found.