Food Technology

Milk, cream and malai fssai standards.

2020-01-24T02:20:00.000-08:00

Milk:- Milk is the normal secretion of the mammary gland of mammals. India has the largest livestock population in the world and ranks high in milk production. India Produces 187.7 million tonnes of milk in 2018-19. Per capita, milk availability In India is 394 gms/day. (Source: Basic Animal Husbandry Statistics, DAHD&F, GoI). U.P. is the top milk-producing state of India with the production of more than 30 million tonnes. However, more than 50% of the milk sector is still unorganized.

	Cow milk	Buffalo milk
Acidity	0.13-0.14%	0.14-0.15%
ph	6.6	6.7
Water content	86.5 %	83.18%
Specific gravity	1.028-1.030	1.030-1.032
fat	3.6	7.4
Freezing temperature	-0.55 to -0.61
Specific heat at 15⁰C	0.938
Boiling	100.2⁰C
Energy	75C/100g	100C/100g

Definitions

LTLT (Low-temperature long time): It involves holding the milk for 62.8⁰C for 30 minutes to eliminate Coxiella burnetii, responsible for Q fever which can be transmitted in milk. It is vat pasteurization method.

HTST: (High temperature and Short time): The use of plate heat exchangers and a continuous operation involves the high-temperature-short-time (HTST) pasteurization process at a temperature of at least 72⁰C for at least 15 sec.

Ultrahigh temperature (UHT): Temperatures of at least 137.8⁰ C in a continuous flow, with holding times of approximately 2 sec to be labeled "ultra-pasteurized."

for cream: Heating is at 71.1⁰ C or above for 30 min by the holding method or 87.7 to 93.3⁰ C for a few seconds by the HTST method.

Vacreation: Rapid heating of cream is accomplished by injecting steam or by a combination of steam injection and evacuation in a process known as vacreation.

STERILISATION : The term “sterilisation when used in association with milk, means heating milk in sealed container continuously to a temperature of either 115⁰C for 15 minutes or at least 130⁰ C for a period of one second or more in a continuous flow and then packed under the aseptic condition in hermetically sealed containers to ensure preservation at room temperature for a period not less than 15 days from the date of manufacture

RECOMBINED MILK = Milk fat + Milk SNF + Water + homogenization + Pasteurisation. Recombined milk shall be pasteurised and shall show a negative Phosphatase Test.

SKIMMED MILKmeans milk from which fat has been removed mechanically and contains little or no fat.

Note: The total urea content in milk shall not be more than 700 ppm.

Milk Class	Designation	Milk fat(%)	Min. milk solids(%)
Buffalo milk	Raw, pasteurized, boiled, flavoured, sterlized	5.0-6.0^*	9.0
Cow milk	Raw, pasteurized, boiled, flavoured, sterlized	3.5-4.0^*	8.5
Mixed milk	Raw, pasteurized, boiled, flavoured, sterlized	4.5	8.5
Standardized milk	Pasteurized, flavoured, sterlized	4.5	8.5
Recombined milk	Pasteurized, flavoured, sterlized	3.0	8.5
Toned milk	Pasteurized, flavoured, sterlized	3.0	8.5
Double toned milk	Pasteurized, flavoured, sterlized	1.5	9.0
Full cream	Pasteurized, sterlized	6.0	9.0
Skimmed milk	Pasteurized, Raw, flavoured, sterlized	Not more than 0.5	8.7

* = As per state

The heat treatment for the various designated milk shall be as follows:

Designation	Heat treatment
Raw	Nil
Pasteurised	Pasteurisation
Boiled	Boiling
Flavoured	Pasteurisation or Sterilisation
Sterilised	Sterilisation

Milk/ Milk product	treatment	Time-temp. combination	Aim
Milk	LTLT Pasteurisation	62.8⁰C for 30 minutes	→Inactivate Alkaline Phosphatase enzyme. →To eliminate Coxiella burnetii.
	HTST Pasteurisation	72⁰C for at least 15 sec
	UHT Pasteurisation	137.8⁰ C for at least 2seconds
	Sterilisation	110-115⁰C for 15-25 minutes or 130⁰C for at least 1 sec.	To ensure preservation at room temperature for a period not less than 15 days from the date of manufacture
CREAM	LTLT Pasteurisation	71.1⁰ C or above for 30 min	→ To complete the neutralization process in the manufacture of butter. → To destroy the undesirable microorganisms and inactivate the enzymes. → To eliminate some of the gaseous tainting substances.
	HTST Pasteurisation	87.7 to 93.3⁰ C for a few seconds
	Vacreation	0.25-0.3 kg steam/kg cream at a velocity of approximately 140 m/s	→ To make possible the removal of some volatile off-flavors by vacreation.

Cream: Cow or buffalo milk fat obtained by direct centrifugation of milk. It shall be free from starch and other ingredients foreign to milk. It may be of the following three categories.

1. Low fat cream—containing milk fat, not less than 25.0 percent by weight.

2. Medium fat cream—containing milk fat, not less than 40.0 percent by weight.

3. High fat cream—containing milk fat, not less than 60.0 percent by weight.

Note:- Cream sold without any indication about milk fat content shall be treated as high fat cream.

A mixture of milk and milk fat of 10 to 12 percent are called half-and-half.

Another classification of cream on the basis of its uses are as follows,

Cream type	Milk fat content (%)
Table cream	18-22
Light cream	20-25
Coffee cream¹	18-25
Heavy cream	30-40
Plastic cream	80
Whipped cream	30-36
Sour cream²	18
Baker's cream	32-40

1 = May contain 0.05% of sodium citrate.

2 = 0.6% lactic acid to provide sour taste.

Cream Powder: The product obtained by partial removal of water from cream.

(i) MoistureNot more than 5.0%

(ii) Milk fatNot less than 42.0 %

(iii) Milk proteinin Milk solid not fat Not less than 34.0 %

MALAI: Malai means the product rich in butterfat prepared by boiling and cooling cow or buffalo milk or a combination thereof. It shall contain not less than 25.0 per cent milk fat.

There will be more post regarding the milk products FSSAI standards.
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Aim of different types of sensory evaluation of foods.

2020-01-14T06:26:00.000-08:00

Today's post is about the aim of different types of sensory evaluations we use in new product development. These are useful in various exams ars typical questions can be formed from such points.

S.no.	Sensory test	AIM
1	Difference test	To evaluate if a difference exists between two or more samples.
1.1	Paired comparison test	A greater or lesser degree of intensity of specified characteristics.
1.2	Triangle test	To determine whether a perceptible sensory difference exists or not between two products.
1.3	Duo-trio test	Determine whether or not a sensory difference exist between two samples. Or To determine whether product differences result from a change in ingredients, packaging, or storage.
1.4	Multiple sample test	Single-factor analysis of the variances of a given sample. Or For odour evaluation. Or To evaluate one sample which is most efficient.
2	Descriptive analysis	Sensory description of sensations that are perceived.
2.1	Flavour profile	Obviate the need for statistical evaluation and discussion of flavour profile and components.
2.2	Texture profile	Evaluation of texture parameters via human and instruments. For Rheological examination of foods.
2.3	Quantitative descriptive analysis (QDA)	To evaluate all of the sensory properties.
3	Affective testing	To measure liking or preference for a product by a consumer.
4	Rating test	To evaluate the intensity of food senses on a scorecard. Use for comparison of two foods via scoring.
4.1	Monadic test	Used for testing foods that have after taste or flavour.
4.2	Two sample difference test	To check the degree of difference between test samples and standard samples.
4.3	Multiple sample difference test	It is used to evaluate more than one test variable with the known standard sample.
4.4	Hedonic test	It is used to measure the degree of pleasurable and unpleasurable experiences on a hedonic scale.
4.5	Numerical scoring test	Use to evaluate a particular characteristic as "excellent, good, fair and poor".
4.6	Composite scoring test	Specific characteristics of a product are rated separately.
5	Sensitivity threshold test	Measure the ability of the individual to smell taste or feel specific characteristics in food and beverages For selecting panel members.

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Microbial spoilage/contamination of various foods- ii

2019-12-28T02:44:00.000-08:00

Below is the list of microbial spoilage of milk, butter, cheese, canned foods, and soft drinks. This list is part-2 of the previous post. This list will help you in the ASRB NET 2019 exam as at least 2 questions are asked every time related to spoilage of milk, meat, poultry, fish, egg, bakery, confectionery. The milk and milk product spoilage and spoilage microorganisms will be uploaded in the second post as soon as possible.

Food Product	Spoilage	Microorganism
1. Milk	Sweet Curding	Pseudomonas fluorescens
	Ropiness (top)	Alcaligenes viscolactis
	Proteinase Production	Pseudomonas fluorescens
	Ropiness (throughout milk)	Enterobacter aerogens
	Burnt or Caramel flavour	Streptococcus lactis
	fishiness	Aeromonas hydrophilla
	Blue milk	Pseudomonas syncyanea
	Yellow milk	Pseudomonas synxantha
	Alkali forming bacteria	Pseudomonas fluorescens
	Brown Milk	Pseudomonas putrefaciens
	Red Milk	Serratia marcescens
2. Butter	Orange-Yellow colour	Oospora lactis
	Maltiness	Streptococcus lactis
3. Cheese	Dark Colour	Cladosporium herbarum
	Skunk like flavour	Pseudomonas mephitica
	Rusty Spot	Lactobacillus Plantarum

4. Canned Food	Flat Sour spoilage	Bacillus
	TA Spoilage	Thermophillic, Anaerobic Bacteria
	Sulphide Stinker	Desulfotomaculum nigrificans
	Spoilage of Canned Fruits	Byssochlamys fulva
	Black Beet	Bacillus betanigrificans
5. Soft drinks	Spoilage	Torulopsis, candida

Moreover, we are coming with the mock test in a few days so you guys can prepare for ASRB NET and GATE XL Food technology also.

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Microbial spoilage of various foods

2019-12-19T06:18:00.000-08:00

Below is the list of microbial spoilage of meat, poultry, fish, egg, honey, confectionery, bakery. This list will help you in ASRB NET 2019 exam as at least 2 questions are asked every time related to spoilage of milk, meat, poultry, fish, egg, bakery, confectionery. The milk and milk product spoilage and spoilage microorganisms will be uploaded in the second post as soon as possible.

Food	Spoilage/contamination type	microorganism
1.Bread	Bread Mold	Rhizopus stolonifer
	Moldy	Rhizopus, Penicillium species
	Pinky or reddish	Monilla sitophilla
	Chalky Bread	Endomycopsis fibuligera, Trichosporon variable
	Ropiness	Bacillus licheniformis Bacillus Subtillis
	Bloody bread or red bread	Serratia marcescens
	Red Crumb	Geotrichum aurantiacum
2. sugar products & syrups candy	Ropy	Enterobacter aerogenes
	Yeasty	Saccharomyces Zygosaccharomyces
	Honey Spoilage	Zygosaccharomyces richteri
	Pink	Micrococcus roseus
	Moldy	Aspergillus, Penicillium
	Salmonoellosis	salmonella
3. Fruits & Vegetables	Bacterial Soft rot	Rhizopus, Erwinia cartovora
	Grey mold rot	Botrytis
	Rhizopus soft rot	Rhizopus nigricans
	Black mold rot	Aspergillus niger
	Watery Soft rot	Sclerotinia sclerotiorum
	Pink Mold rot	Trichothecium roseum
	Souring	Saprophytic bacteria
	Blue mold rot	Penicillium digitatum
	Black rot	Alternaria, Physalospora
	Green mold rot	Cladosporium
	Anthracnose	Colletotrichum linedemuthianum
4.Pickles, Saurekraut	Film Yeasts & Pink Yeasts	Rhodotorula
	Black pickle	Bacillus nigricans
	Undesirable Odour in saurekraut	Padeococcus cerevisae
	Pickle Softening	Penicillium
	Pectolysis	Aeromonas
	Slimy Kraut	Lactobacillus cucumeris
	Bloats	Lactobacillus plantarum
5. Meats	Red Spot	Serratia marcescens
	Blue color	Pseudomonas syncyanea
	Earthy flavor	Actinomycetes
	Souring	Pseudomonas, Micrococcus, Bacillus
	Moldy	Aspergillus, Rhizopus, Penicillium
	Putrefaction and canned meat spoilage	Clostridium
	Green patches	Penicillium expansum
	Whiskers	Thamnidium
	Slimy	Leuconostoc
6. Fish	Discoloration	Pseudomonas
	Smoked fish spoilage	Molds
	Pink discoloration of salted fish	Helicobacterium, Helicococcus, Pseudomonas salineria
	Dun spoilage	Wallemia sebi
7. Egg	Green rot	Pseudomonas fluorescens
	Fungal red rot	Sporotrichum
	Black rot(opaque egg)	Proteus
	Red rot	Serratia marcescens
	Colorless rot	Pseudomonas, Alcaligenes
8. Poultry	Slime, Odour	Pseudomomas, Alcaligenes

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Manufacturing aspects of Probiotics and Prebiotics

2019-12-11T01:41:00.000-08:00

Hello all, the first Post of this blog is about the manufacturing aspects of Probiotics and Prebiotics.

So let's continue,

Introduction:- Various types of microorganisms, known as gut microbiota, are inhabitants of the human gastrointestinal tract. It has been reported that there are live microorganisms per gram in the human colon. The resident microbial groups in the stomach, small, and large intestine are crucial for human health. The majority of these microorganisms, which are mostly anaerobes, live in the large intestine. Although some endogenous factors, such as mucin secretions, can affect the microbial balance. The human diet is the chief source of energy for their growth. Particularly, non-digestible carbohydrates can highly modify the composition and function of gut microbiota. Beneficial intestinal microbes ferment these non-digestible dietary substances called prebiotics and obtain their survival energy from degrading indigestible binds of prebiotics. As a result of this, prebiotics can selectively influence gut microbiota. On the other hand, the gut microbiota affects intestinal functions, such as metabolism and integrity of the intestine. Moreover, they can suppress pathogens in healthy individuals through the induction of some immunomodulatory molecules with antagonistic effects against pathogens by lactic acid that is produced by Bifidobacterium and Lactobacillus genera.

Prebiotics:- Prebiotics are compounds in food that induce the growth or activity of beneficial microorganisms such as bacteria and fungi. The most common example is in the gastrointestinal tract, where prebiotics can alter the composition of organisms in the gut microbiome. Dietary prebiotics is typically non-digestible fiber compounds that pass undigested through the upper part of the gastrointestinal tract and stimulate the growth or activity of advantageous bacteria that colonize the large bowel by acting as a substrate for them. Fermentation is the main mechanism of action by which prebiotics are used by beneficial bacteria in the colon.

Both Bifidobacteria and Lactobacillus are bacterial populations that use saccharolytic metabolism to break down substrates. The bifidobacterial genome contains many genes that encode for carbohydrate-modifying enzymes as well as genes that encode for carbohydrate uptake proteins. The presence of these genes indicates that Bifidobacteria contain specific metabolic pathways specialized for the fermentation and metabolism of plant-derived oligosaccharides, or prebiotics. These pathways in Bifidobacteria ultimately produce short-chain fatty acids, which have diverse physiological roles in body functions.

Process steps ( From rye bran to prebiotic products ):- The prebiotics are obtained normally through enzymatic processes or extraction from natural food.

The first step in our process consists of screening potential prebiotic-producers from microbial culture collections.
The selected organisms are further used for process development. Process optimization is conducted at several levels, namely medium composition, operational conditions including downstream processing, and scale-up.
Finally, the produced compounds are tested for their prebiotic activity using an in-vitro gut model.
The process steps are as follows:-

Heat pretreatment

↓

Starch degradation (via amylase & amyloglucosidase)

↓

Protein degradation (Via protease)

↓

Separation steps to remove small molecules (via ethanol precipitation)

↓

Xylan hydrolysis (via xylanase)

↓

prebiotic oligosaccharides (product)

There are some other types of prebiotics also such as

GOS, FOS. The process steps may vary according to the demand for probiotics and substrate.

Probiotics:- Probiotic defined according to the Food and Agriculture Organization of the United Nation and the World Health Organization as “Live microorganisms which when administered in adequate amounts confer a health benefit on the host". Synbiotic products are a combination of probiotics and prebiotics. The prebiotic substances are adapted to the demands of the probiotic microorganisms. Hence their survival and proliferation are increased.

In general, it is assumed that the microorganisms should reach the large intestine alive. Therefore they have to be able to withstand the conditions in the gut with a pH value down to 0.8 and the proteolytic activity of the pepsin. Probiotic strains of Lactobacillus acidophilus belong to the most stable lactic acid bacteria under these conditions. Industrial processes for food culture production, including probiotics, almost exclusively use conventional batch fermentation with suspended cells.

Fermentation

↓

Strain selection

↓

Blending

(The bacterial strains and protective and nutritional ingredients of the are mixed on a carrier material.)

↓

Testing

(After the formulation is produced, the complete formulation is tested in vitro on real-time stability, gastrointestinal survival, and metabolic activity.)

↓

Packaging

Here are some recommendations for various competitive exams....like csir-net, Icar-net or Asrb-net, UGC-net, gate food technology or food safety officer