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冷冻食品保质期试验.pdf
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Shelf Life Testing:
Z7t-p(|xi*Q0Procedures and Prediction Methods for Frozen
7l5u~ D$w&? I0Foods食品伙伴个性空间H.}*AQ0@8V"h
Bin Fu食品伙伴个性空间*D#HAism V$WO.?6v
Kellogg's Battle Creek MI食品伙伴个性空间ha1wk:n;[M@+ZM}
Theodore P. Labuza食品伙伴个性空间/F)W\r:f(w
Dept. of Food Science & Nutrition, University of Minnesota食品伙伴个性空间"D6@(z ~5@5@z_
1334 Eckles Ave., St. Paul, MN 55108食品伙伴个性空间5Qa7nW4tMkb^+D
2
i)k9z0\h p4A\5V+SP2bY019.1 Introduction
^ ` qlIQz0The shelf life of a food can be defined as the time period within which the food is safe食品伙伴个性空间 Pe*Z J;v
to consume and/or has an acceptable quality to consumers. Just like any other food,食品伙伴个性空间j1W)G"e8Rw&b.~t5L
frozen foods deteriorate during storage by different modes or mechanisms, as
)b(MG6V]9i]2x*M'f0T^0summarized in Table 1. Microbes usually are not a problem since they cannot grow at食品伙伴个性空间fM+k{\7g3]6M+@
freezing temperatures unless subjected to extensive temperature abuse above the
Rh {Jc7x+c'w XbX,_0freezing point. Enzymes are a big concern for frozen foods, which can cause flavor食品伙伴个性空间)^1m]Y1N\!__ks7~
change (lipoxygenase) in non-blanched fruits and vegetables and accelerated
!}4@ vN2HY0deterioration reactions in meat and poultry (enzymes released from disrupted食品伙伴个性空间Xo'aLlLMQU+b
membranes during precooking). Cell damage or protein and starch interactions during
T`|fZ)I]0freezing cause drip and mushiness upon thawing. Discoloration could occur by nonenzymatic食品伙伴个性空间~~_`R#T8P
browning, bleaching, and freezer burn. Vitamin C loss is often a major食品伙伴个性空间6B] @7gOcyL
concern for frozen vegetables. Physical changes, such as package ice formation,
)D |1mA(l~:Z i0moisture loss, emulsion destabilization, recrystallization of sugars and ice of frozen食品伙伴个性空间%L$n x5xk)c-B4U*R
desserts are often accelerated by fluctuating temperatures.食品伙伴个性空间J tDL7j
For any specific frozen product, which mode determines its shelf life, depends
wR#[vKTG@/zv0s U0on the product characteristics (raw materials, ingredients, formulation), pre-freezing食品伙伴个性空间K:[%uv%Xh3N3a~@A U
treatment, freezing process, packaging film and processes, and of course storage
f$D x.|4O0conditions. All of the quality deterioration and potential hazards are usually
Gqq'JN2cp3D0O0exaggerated or complicated by a fluctuating time-temperature environment (e.g.
'XK].u1x d.?2m} _0freeze/thaw cycle) during storage. On the other hand, the shelf life of a frozen food
*Hn[#{ B(x#U;~P"r{(^0can be extended through ingredient selection, process modification and change of食品伙伴个性空间8S"f|%s8EeaW
package or storage conditions, as discussed in Section 3 of this book.
%f8W*pkI0This chapter will focus on shelf life testing of frozen foods for product食品伙伴个性空间:wMmrh_h!A
development and market practices. Shelf life testing consists basically of selecting the食品伙伴个性空间b o,B1spN(W
quality characteristics which deteriorate most rapidly in time and the mathematical
'u;_X,Q$NOAvf0M0modeling of the change. Table 19.1 can be used as a reference for the selection of
P ZW*Z+od0quality characteristics, which depends on the specific product and usually requires
]mm.\;Z2Z;\a0professional judgment. Mathematical modeling of quality deterioration will be
h&kH/\ e4y+k3X2c,i0discussed next.食品伙伴个性空间BSk(} Vq2J,Z
3食品伙伴个性空间2Z}%O F!hQ2dm&Q
Table 19.1 Deterioration modes of frozen foods食品伙伴个性空间+yJ1k7]5mr
Frozen Foods Deterioration Modes食品伙伴个性空间`E*?u!G:R;|V,T
Frozen meats, poultry and seafood Rancidity
)?\(bfb$kr9\0Toughening (protein denaturation)食品伙伴个性空间 n Qt|i
Discoloration食品伙伴个性空间/N6@vI[ Z [
Desiccation (freezer burn)
6m3s2snYf N*D?2w0Frozen fruits and vegetables Loss of nutrients (vitamins)
2U E*L$Z ^:[z f?0Loss of texture (temperature abuse)食品伙伴个性空间uKx1c.E*d
Loss of flavor (lipoxygenase, peroxidase)
0x7s O FQ,v8x#dO0Loss of tissue moisture (forming package ice)
+cY l$}1X5D k/m(hV}0Discoloration食品伙伴个性空间&H;wS/^!i$Q+|!o
Frozen concentrated juices Loss of nutrients (vitamins)食品伙伴个性空间:FiT#Nf f R
Loss of flavor食品伙伴个性空间)dNCZ ]#{1I
Loss of cloudiness
dcZ9q's~%f;W&}1V3?u0Discoloration
ev$lX:w NY9B.B0Yeast growth (upon temperature abuse)食品伙伴个性空间){b2Ff(J
Frozen dairy products
)Tt}UQ9h ZQ0(ice cream, yogurt, etc.)
cd4f[%Y2X0Iciness (recrystallization of ice crystals)
|4lh$o] Z+Z0Sandiness (lactose crystallization)
A%I ]b D+w+e;S?0Loss of flavor
3~M!Px$WBv0Disruption of emulsion system食品伙伴个性空间2N,Lw%U)}i/^e
Frozen convenience foods Rancidity in meat portions食品伙伴个性空间6AV(l"^q5J
Weeping and curdling of sauces食品伙伴个性空间rY2RS(b%|;E@O
Loss of flavor
0xx2xcC*n O{0Discoloration食品伙伴个性空间 C D'N G6h.E,B t
Package ice
Y^ j%K Ka,F3]0Frozen bakery products (raw dough,
&V)|2Vs;pZ]0bread, croissants)食品伙伴个性空间n6K-@ W:T/UY/e._y
Burst can (upon temperature abuse) (dough)食品伙伴个性空间a1p[ E6Lo
Loss of fermentation capability (dough)
4|9Bg y'z0Staling (becoming leathery)
q#Tj2a sz:d7sZ0Loss of fresh aroma
b:wO]W+G2e#B019.2 Modeling of quality deterioration食品伙伴个性空间_om,Y V
19.2.1 Basic equation
@is$yPg!bx0j(P0A frozen food starts to degrade once it is produced (Figure 19.1). The rate and食品伙伴个性空间"X)J%}{XL(H
the degree of degradation depends on both the composition and the environmental
ex"Ca$i*tu0conditions during storage and distribution. In general, the loss of food quality or shelf食品伙伴个性空间1od]4?z0i$l%M
life is evaluated by measuring a characteristic quality index, "A". The change of quality食品伙伴个性空间U Zdr7v4X
index A with time (dA/dt) can usually be represented by the following kinetic equation:
(g:Z9{}F F0- dA/dt = k An (19.1)
`? w4{+Es%{"S*rH5G0where k is called a rate constant depending on temperature, product and packaging
Z7t-p(|xi*Q0Procedures and Prediction Methods for Frozen
7l5u~ D$w&? I0Foods食品伙伴个性空间H.}*AQ0@8V"h
Bin Fu食品伙伴个性空间*D#HAism V$WO.?6v
Kellogg's Battle Creek MI食品伙伴个性空间ha1wk:n;[M@+ZM}
Theodore P. Labuza食品伙伴个性空间/F)W\r:f(w
Dept. of Food Science & Nutrition, University of Minnesota食品伙伴个性空间"D6@(z ~5@5@z_
1334 Eckles Ave., St. Paul, MN 55108食品伙伴个性空间5Qa7nW4tMkb^+D
2
i)k9z0\h p4A\5V+SP2bY019.1 Introduction
^ ` qlIQz0The shelf life of a food can be defined as the time period within which the food is safe食品伙伴个性空间 Pe*Z J;v
to consume and/or has an acceptable quality to consumers. Just like any other food,食品伙伴个性空间j1W)G"e8Rw&b.~t5L
frozen foods deteriorate during storage by different modes or mechanisms, as
)b(MG6V]9i]2x*M'f0T^0summarized in Table 1. Microbes usually are not a problem since they cannot grow at食品伙伴个性空间fM+k{\7g3]6M+@
freezing temperatures unless subjected to extensive temperature abuse above the
Rh {Jc7x+c'w XbX,_0freezing point. Enzymes are a big concern for frozen foods, which can cause flavor食品伙伴个性空间)^1m]Y1N\!__ks7~
change (lipoxygenase) in non-blanched fruits and vegetables and accelerated
!}4@ vN2HY0deterioration reactions in meat and poultry (enzymes released from disrupted食品伙伴个性空间Xo'aLlLMQU+b
membranes during precooking). Cell damage or protein and starch interactions during
T`|fZ)I]0freezing cause drip and mushiness upon thawing. Discoloration could occur by nonenzymatic食品伙伴个性空间~~_`R#T8P
browning, bleaching, and freezer burn. Vitamin C loss is often a major食品伙伴个性空间6B] @7gOcyL
concern for frozen vegetables. Physical changes, such as package ice formation,
)D |1mA(l~:Z i0moisture loss, emulsion destabilization, recrystallization of sugars and ice of frozen食品伙伴个性空间%L$n x5xk)c-B4U*R
desserts are often accelerated by fluctuating temperatures.食品伙伴个性空间J tDL7j
For any specific frozen product, which mode determines its shelf life, depends
wR#[vKTG@/zv0s U0on the product characteristics (raw materials, ingredients, formulation), pre-freezing食品伙伴个性空间K:[%uv%Xh3N3a~@A U
treatment, freezing process, packaging film and processes, and of course storage
f$D x.|4O0conditions. All of the quality deterioration and potential hazards are usually
Gqq'JN2cp3D0O0exaggerated or complicated by a fluctuating time-temperature environment (e.g.
'XK].u1x d.?2m} _0freeze/thaw cycle) during storage. On the other hand, the shelf life of a frozen food
*Hn[#{ B(x#U;~P"r{(^0can be extended through ingredient selection, process modification and change of食品伙伴个性空间8S"f|%s8EeaW
package or storage conditions, as discussed in Section 3 of this book.
%f8W*pkI0This chapter will focus on shelf life testing of frozen foods for product食品伙伴个性空间:wMmrh_h!A
development and market practices. Shelf life testing consists basically of selecting the食品伙伴个性空间b o,B1spN(W
quality characteristics which deteriorate most rapidly in time and the mathematical
'u;_X,Q$NOAvf0M0modeling of the change. Table 19.1 can be used as a reference for the selection of
P ZW*Z+od0quality characteristics, which depends on the specific product and usually requires
]mm.\;Z2Z;\a0professional judgment. Mathematical modeling of quality deterioration will be
h&kH/\ e4y+k3X2c,i0discussed next.食品伙伴个性空间BSk(} Vq2J,Z
3食品伙伴个性空间2Z}%O F!hQ2dm&Q
Table 19.1 Deterioration modes of frozen foods食品伙伴个性空间+yJ1k7]5mr
Frozen Foods Deterioration Modes食品伙伴个性空间`E*?u!G:R;|V,T
Frozen meats, poultry and seafood Rancidity
)?\(bfb$kr9\0Toughening (protein denaturation)食品伙伴个性空间 n Qt|i
Discoloration食品伙伴个性空间/N6@vI[ Z [
Desiccation (freezer burn)
6m3s2snYf N*D?2w0Frozen fruits and vegetables Loss of nutrients (vitamins)
2U E*L$Z ^:[z f?0Loss of texture (temperature abuse)食品伙伴个性空间uKx1c.E*d
Loss of flavor (lipoxygenase, peroxidase)
0x7s O FQ,v8x#dO0Loss of tissue moisture (forming package ice)
+cY l$}1X5D k/m(hV}0Discoloration食品伙伴个性空间&H;wS/^!i$Q+|!o
Frozen concentrated juices Loss of nutrients (vitamins)食品伙伴个性空间:FiT#Nf f R
Loss of flavor食品伙伴个性空间)dNCZ ]#{1I
Loss of cloudiness
dcZ9q's~%f;W&}1V3?u0Discoloration
ev$lX:w NY9B.B0Yeast growth (upon temperature abuse)食品伙伴个性空间){b2Ff(J
Frozen dairy products
)Tt}UQ9h ZQ0(ice cream, yogurt, etc.)
cd4f[%Y2X0Iciness (recrystallization of ice crystals)
|4lh$o] Z+Z0Sandiness (lactose crystallization)
A%I ]b D+w+e;S?0Loss of flavor
3~M!Px$WBv0Disruption of emulsion system食品伙伴个性空间2N,Lw%U)}i/^e
Frozen convenience foods Rancidity in meat portions食品伙伴个性空间6AV(l"^q5J
Weeping and curdling of sauces食品伙伴个性空间rY2RS(b%|;E@O
Loss of flavor
0xx2xcC*n O{0Discoloration食品伙伴个性空间 C D'N G6h.E,B t
Package ice
Y^ j%K Ka,F3]0Frozen bakery products (raw dough,
&V)|2Vs;pZ]0bread, croissants)食品伙伴个性空间n6K-@ W:T/UY/e._y
Burst can (upon temperature abuse) (dough)食品伙伴个性空间a1p[ E6Lo
Loss of fermentation capability (dough)
4|9Bg y'z0Staling (becoming leathery)
q#Tj2a sz:d7sZ0Loss of fresh aroma
b:wO]W+G2e#B019.2 Modeling of quality deterioration食品伙伴个性空间_om,Y V
19.2.1 Basic equation
@is$yPg!bx0j(P0A frozen food starts to degrade once it is produced (Figure 19.1). The rate and食品伙伴个性空间"X)J%}{XL(H
the degree of degradation depends on both the composition and the environmental
ex"Ca$i*tu0conditions during storage and distribution. In general, the loss of food quality or shelf食品伙伴个性空间1od]4?z0i$l%M
life is evaluated by measuring a characteristic quality index, "A". The change of quality食品伙伴个性空间U Zdr7v4X
index A with time (dA/dt) can usually be represented by the following kinetic equation:
(g:Z9{}F F0- dA/dt = k An (19.1)
`? w4{+Es%{"S*rH5G0where k is called a rate constant depending on temperature, product and packaging