Sweet sour bitter salty texture crispiness smoothness

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Unformatted text preview: ity control Objective testing for quality (varies with each commodity) Quality control charts - plot quality testing over time Establish control limits 100 Red = out of control Yellow = use caution Green = average 80 60 40 20 0 1 2 3 4 5 6 7 8 Appearance Size and shape Size is easily measured Weight Count (per box) Visually Automated sorters Shape is more difficult to measure Appearance Color Very important Several ways to measure Instrumental Sensory panel Appearance Color Spectrophotometer for liquids – light absorbed Tristimulus colorimeters = measure light reflected from food L – Lightness to Darkness a - Red to Green b - Yellow to Blue Color Space L= lightness (white= 100) a= (-) green b= (+) yellow b= (-) blue L= lightness (black=0) a= (+) red Appearance Color Visually comparing foods to standardized colored tiles or pictures Gloss The "shine" of a food Determined by the way light reflected Color measurement of baked goods Pigments and colorants Many natural and artificial colorants added to foods Some also add flavor Very complex Many different compounds Often unstable (add antioxidants?) Very important food additives Not all colorants are legal in foods Constituents of Foods Natural Pigments and color most common: Myoglobin = meat Chlorophyll = green vegetables Carotenoids = orange, yellow fruits and veggies Anthocyanins = red, blue fruits Betalains = violet-red, yellow in beets Please be able to describe the natural pigments listed in this table and their properties Pigments and Colors Pigments can be degraded Heat, air (oxidation), enzymes, etc. Brown pigment formation Carmelization of sugars Maillard reaction : reducing sugars and amino acids Beef What’s for dinner t both hemoglobin and myoglobin Meat containsonight? that binds oxygen The bright red color of fresh cut meat is due to oxymyoglobin (oxygenation) The red color fades as oxidation occurs, conversion of Fe+2 to ferric (Fe+3) state Forms of Myoglobin...
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This document was uploaded on 02/01/2014.

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