Lemon Curd Sauce

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Lemon Curd Sauce

• Group Members
• Akou Amefia
• Kari Alderman
• Shivakumar Elayedath
• Tiffany Gregory
• Carrie Mueller
• Luis Rodriguez-Romo
• Hector Ruiz-Espinosa
• FST 696
• Spring 2000

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What is Lemon Curd?

• Traditional English dessert sauce.
• Eggs, butter, sugar, lemon juice.
• Gourmet product.
• Some national and imported brands available on
  the market, but none have neither the
  organolpetic properties of the original nor only
  its ingredients (other food additives).

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Issues

• To take a kitchen recipe to an industrial
  operation
• Desired shelf life stability, 1 year
• No additives
• No preservatives

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Glorious Gourmet

• Gourmet Food Company, based in Ohio.
• Specialty stores, several products in the market.
• Target market
• Upper class
• People who eat what is IN
• Not health conscious

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Usage of Lemon Curd

• Spread on muffins, croissants, and other breads
• A filling for pies and tarts

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Role of Eggs

• Multifunctional properties
• coagulation
• foaming
• emulsion forming

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Coagulation

• Coagulation can be achieved by
• heating
• acid addition
• Factors affecting coagulation
• temperature (62-65oC)
• Sugar increases temperature of coagulation
• Acid lowers time and temperature of coagulation

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Emulsion formation

• Lipoproteins and phospholipids in egg yolk help
  in emulsification
• Factors affecting emulsion formation
• Viscosity
• Heating yolk to 63oC
• Fermentation of yolk with pancreatic lipase

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Role of butter

• Butter gives the product
• flavor
• texture and mouthfeel of the product
• Phospholipids in the fat globule membrane of the
  butter also give the product some emulsification
• Oxidative stability is high
• high content of saturated fatty acids
• low in poly-unsaturates
• Has natural antioxidants which reduce lipid
  oxidation

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Lemon juice

• Average pH - 2.3
• Main component citric acid
• Role in Lemon curd
• Flavor (tartness lemon flavor)
• Protein denaturation (body, texture mouth feel)
• Acidulant (antimicrobial agent)
• Citric acid sequesters the metals prevents lipid
  oxidation

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Sugar

• Sweetening agent
• Balances natural acidity in fruits
• Reduces water activity by binding free water
• Increases microbial stability
• Protects egg proteins from acid and heat
  denaturation
• Prevents syneresis
• Participates in browning reactions ( acid
  hydrolysis)

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Lemon oil

• Responsible for the pungency of flavor(aldehyde
  ester)
• Most important flavor component is citral (neral
  gerenial)

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METHODOLOGY RESULTS
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Processing Method

• Equipment
• Steam kettles Howlett Hall
• Stephan UMC V Electronic Batch Process
• Variables
• Order of addition
• Preblending eggs, butter, sugar
• Addition of lemon juice as last ingredient

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Processing Method

• Variables
• Cooking Temperature
• Processing Method (using Stephan UMC)
• Pre-blending of eggs, sugar and butter
• Addition of remaining ingredients
• Bring to 104F
• Hot fill into glass jars
• Remaining heat treatment in 170F water bath

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Emulsion Stability method and results

• Oil separation on subjecting product to high
  temperature and centrifugation (Pai,1995)

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pH and TA Methodology.

• Titratable acidity
• Measurement of acidity within a sample . It
  is expressed in terms of citric acid
• pH
• Measured using Fisher Accumet? pH Meter Model
  630

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TA and pH Results.
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Aw and Viscosity Methodology

• Water activity
• Measured using a Decagon CX-2 Water Activity
  Meter on some of our samples and ranged from
  0.949 to 0.950.
• Viscosity Measurements
• A Brookfield Viscometer (model DV) was used .
  Spindle 4 was used at a speed of 1.0RPM for 2
  minutes.

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Viscosity results
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Color Analysis Methodology

• Instrument HunterLab Ultrascan colorimeter
• Readings made on 150F fill, 170F fill, water
  bath, and original order of addition samples
  using square glass sample holders
• L, a, and b values obtained
• L lightness
• Positive a red, Negative a green
• Positive b yellow, Negative b blue

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Color AnalysisResults for L-values over time
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Color AnalysisResults for a-values over time
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Color AnalysisResults for b-values over time
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Color Analysis Results

• No statistically significant differences were
  found
• General trend L decreases over time
• After 14 days of accelerated shelf life at 37C
• water bath sample has highest L-value

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Sensory Analysis Methodology

• Descriptive analysis used
• Panel Lemon curd group members
• Scoresheet Unstructured line scale
• Attributes
• Color
• Lemon flavor
• Sweetness
• Smoothness
• Thickness

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Sensory Analysis Methodology(continued)

• 150F fill, 170F fill, water bath, and original
  order of addition samples were analyzed at 0, 7,
  and 14 days of accelerated shelf life (37C)
• Data quantified by ruler
• Data analyzed by ANOVA and Tukeys pairwise
  comparisons using SAS at 5 significance level

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Average Panel Scores for Lemon Curd Attributes
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Sensory Analysis Results

• Lack of statistically significant differences
• Many sources of variation
• Differences found in
• Color water bath lighter in yellow color
• Correlates with color data
• Lemon original order of addition most intense
• Thickness 150F fill least thick
• Correlates with viscosity measurements

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MICROBIOLOGICAL ANALYSIS OF LEMON CURD
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Methodology

• Simulated extended shelf life of product at
  25 37 C
• TOTAL PLATE COUNT (Plate Count Agar)
  Presence of aerobic mesophiles
• YEASTS MOLDS
• Acidified Potato Dextrose Agar (PDA)
  
• Identification of yeast molds

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Methodology, Conditions

• PREPARATIONS OF LEMON CURD (DIFFERENT.
  PREPARATION CONDITIONS)
• SHELF-LIFE T
  25 37 C
• TIME
  DAYS (1- gt7)

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Microbiological results
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Microbiological results

• Not detectable bacterial plate count
• (lt 10 cfu/g in more than 7 days at 25 37 C)
• Growth of molds (Rhizopus spp.) in seven days

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Recommendations

• Use of antimicrobial agent sodium benzoate at up
  to 0.1
• Keep the product refrigerated after opening
• Water bath heating after filling