خصائص التعامل مع العجين Dough Handling Properties

جودة القمح ومنتجاته من دقيق وسميد وزوائد ومواصفات الدقيق المناسب لكل صناعة وفنيات الاختبارات والتحليلات المعملية - جودة الدقيق - جودة السيمولينا / السميد ، الفارينا - جودة الردة الخشنة - جودة الردة الناعمة - جودة السنون shorts/pollard (السن الابيض ، السن الأحمر) من تحليلات واختبارت جودة القمح - Wheat Quality ، كل ما يخص اساليب ضبط الجودة من اختبارات وتحاليل وتحقيق مواصفات وما يتعلق بنظم توكيد الجودة و شهادات الجودة & الاختبارات والاجهزة المعملية وقيمها ودلالتها - Laboratory Instruments ويضم الاختبارات والتعاريف والمانيوال الخاصة بالاجهزة المستخدمة فى المعامل وقيمها ودلالتها ... تطبيقات توكيد الجودة و متطلبات سلامة الغذاء Food Safety-Safe Food-
تطبيقات اشتراطات و متطلبات أمان وسلامة الغذاء Food Safety Management Systems safety , Hygiene , GMP , GHP , ISO22000 , FSSC , ....etc - النظافة الميكانيكية وتكنولوجيا التعقيم و التبخير و مكافحة الآفات - Mechanical Cleaning & Fumigation & Pest Control
آليات وطرق تنظيف المعدات و عمليات النظافة الميكانيكية وما يخص الاساليب التطبيقية و الوقائية فى تكنولوجيا التبخير و التعقيم و مكافحة الافات - التعقيم و التبخير و تكنولوجيا مكافحة الافات - Mechanical Cleaning of Machines & Fumigation & Pest Control Technology ... المحسنات واضافات الدقيق - Flour improvers & Flour additives
يضم ما يتعلق بمحسنات واضافات الدقيق
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خصائص التعامل مع العجين Dough Handling Properties

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Dough Handling Properties

One of the goals of the mixing process in breadmaking is to achieve an optimum and proper balance of dough handling properties. There are 4 major dough handling properties:

1. Extensibility

2. Elasticity

3. Resistance to deformation (tenacity)

4. Stickiness

At the bakery, frequent complaints such as “the dough is too tough” or “the dough has too much pan flow” or “let’s decrease water, the dough is too sticky” are often discussed. Bakers always aim to produce the best dough possible for the makeup stage. A big portion of the credit for baking a high-quality bread goes to the handling properties of dough.

How does it work?
It is important to understand what the handling properties of dough mean, how they are affected and how they affect the finished products.

• Extensibility: Ability of the dough to be stretched, extended or elongated when forces, stress and pressures are applied to it. A certain amount of extensibility is necessary for a dough to be moulded into different shapes. An extensible dough has the ability to stretch (expand) as the gas pressure from yeast fermentation builds up.

• Elasticity: Ability of the dough to regain its original shape after a deforming force has been applied and removed. Simply put, it is the ability of a dough to spring back when it is stretched.

• Resistance to deformation (tenacity): Ability of the dough to resist deformation when being stretched. A dough with too much tenacity is difficult to work with during makeup. Laminated doughs that are too tenacious are often difficult to roll out.

• Stickiness: Ability of the dough to stick to the surfaces which they come into contact with. Dough needs to have minimum stickiness to be properly shaped and conveyed during makeup stages. In most cases, dough stickiness is the least desired property given the operational and cleaning issues that a bakery has to deal with. The simplest way of modifying the stickiness of dough is by increasing or decreasing water absorption.

Application
First, it is important to note that a bread dough is not a simple material. The four handling properties of a dough piece respond proportionally to its non-Newtonian behavior.

It is the presence of gluten-forming proteins which allows wheat doughs to exhibit a viscoelastic behavior with fluid-like (viscous) and solid-like (elastic) components.

Optimizing dough properties
In general, a dough should have good extensibility and just enough elasticity to retain gasses yet expand sufficiently during proofing and baking (oven spring) while retaining its original or desired form.

Similarly, a dough should have as little resistance to deformation as possible to allow for a proper moulding while preserving the “delicate” cell structure.

The balance between elasticity and extensibility may of course change depending on the product and dough needed. For example, hearth breads require good extensibility and good elasticity otherwise the loaves could flatten out rather than bake up high and round.

Aspects that influence dough handling properties
• Wheat class used at the mill (% extraction)

• Hydration (water absorption)

• Percentage of functional polymers (i.e. arabinoxylans, gluten-forming proteins, damaged starch)

• Quality of gluten-forming proteins (gliadins and glutenins)

• Presence of bran particles (exerting a cutting or disrupting action on the gluten matrix)

• Presence of some non-wheat cereal flours

• Mixing conditions (rpm, work input, mix time)

• Overmixing/undermixing

• Degree gluten development

• Dough temperature

• Presence of water-competing ingredients (e.g. sugars, salt, egg proteins) that limit the hydration of functional polymers

• Addition of functional ingredients, such as oxidizing and reducing agents

• Length of dough resting period

Characteristics of a dough that is too extensible, with very low elasticity and poor resistance to deformation:

Processing

• Slack dough

• Poor machining

• Possible overmixing (dough too warm and sticky)

• Too much pan flow

• Excessive water absorption

Finished product

• Sharp corners

• Possible damage to bags

• Excessive volume or product collapse due to excessive oven spring

If a dough is too elastic, with very low extensibility and too much resistance to deformation, it will exhibit the following characteristics during processing:

• Dough mixing: possible undermixing (dough too stiff, tight and/or tough), insufficient water absorption.

• Dough pump: excessive friction against equipment surfaces causes excessive heat which increases dough temperature beyond allowable limits (promoting excessive gas production).

• Dough divider: bucky or gassy dough could cause considerable scaling weight variations.

• Dough sheeting and moulding: poor machining as moulder and sheeter settings (pressures) must be increased (tightened) to form the final dough shape leading to cell structure damage, excessive ‘spring-back’ after application of stress, poor pan flow.

As a result, the finished product will have too round of corners, wild break and shred, and poor symmetry, volume and diameter (in the case of pizza crusts).

Proofer Design
What is Proofer Design?

A proofer is a piece of equipment designed to provide a specific temperature and relative humidity conditions to boost yeast activity of the fermenting dough pieces.

Proofing equipment provides convective surface heating and conduction of heat from the dough surface to its interior. Typical proofing conditions essential for optimum quality yeast-leavened bakery products include:

• Temperature: 95–110°F (35–43°C)

• Relative humidity: 80–85%

• Cycle time: 40–70 minutes

How does it work?
Compared to ovens and other thermal processing equipment used in bakeries, design of high-speed proofers is less complex and can be operated at much milder conditions.

They range from manual to completely automated. Heat and humidity conditions are controlled by air conditioning systems that operate either by steam injection or water spraying (atomized), or a combination of the two.

Steam injection proofers
Saturated steam at low pressure, from a remote or built-in boiler, is released into the air to bring the internal proofer atmosphere to the humidity set point (%RH) for proofing. Temperature of the moist air is controlled by heat exchangers, usually radiators.

How does steam injection effect bread?
Water spraying proofers

Instead of using steam to increase the air moisture content, atomized water is sprayed from nozzles to maintain the dough’s moist external surface. The humid air is also heated by heat exchangers to set the required temperature.

Conditions provided by the proofer help ensure moist dough external surface moist. Formation of a dry skin is an indication of improperly functioning/designed proofer.

Aspects of proofer design
Designing bread proofers follows standard approach to equipment design, including:

• Mass and energy balances

• Process modeling

• Process simulation

• Equipment sizing

• Equipment rating

• Equipment costing

Application
Proper proofer design, especially flow rates and capacity should be matched very closely to those of the baking oven. This helps in preventing issues with scheduling and minimizing idle times. Proofers considerably with larger capacity than baking ovens risk wasting capital and floor space.

Considerations for oven design:
• Product and pan dimensions (width and length)

• Pan capacity (dough pieces per pan)

• Shelf surface area required to proof a given number of pans (per shelf) at a given production rate (units/batch or units/min)

• Spacing between pans

• Capacity/throughput required plus long-term business growth (units/batch or units/min)

• Hygienic design (e.g. condensate collection and drain systems, elimination of dead cornes, cleanable surfaces)

• Mode of operation whether in batch (rack or cabinet proofers) or continuous modes where the dough pieces need to travel very long distances (1,500–4,000 ft or 460–1,220 m) to maintain normal proofing times (40–70 min for most breads and rolls)

The following are useful formulas for calculating the capacity of proofing equipment:
صورة
Capacity of continuous-mode proofers follow the same logic as batch proofers; the only difference is that the baking time in continuous equipment is controlled by the conveying speed.

Continuous proofers

Continuous proofing units are common in large-scale and high-speed bakeries. Their capital cost is considerably much higher than batch-mode proofers but they radically reduce labor cost and minimize production management issues.

They can usually provide automatic dough loading and unloading. Dough pieces travel resting on individual trays, shelves, moving racks or conveyor systems. This mode of operation improves product uniformity as each dough piece is exposed to the same proofing conditions throughout the travel length.

Engineering components to integrate in dough proofers design include:

• Electrical components (e.g. motors)

• Mechanical components (e.g. conveyors, gears, transmission belts, chains)

• Thermal components (e.g. source/generation of saturated steam, water atomizing systems/nozzles, steam dampers, insulation materials to minimize heat loses)

• Pan supporting systems

• Electronics and automation systems

• Instrumentation and control devices

• General construction components (e.g. equipment walls, supports, doors, racks, shelves)

Packaging Temperature
Packaging temperature is the optimum temperature of a baked product which has just been cooled and sliced and is ready for placement in a protective bag or container.

This temperature point or range are designed to ensure proper moisture level to avoid condensation, thus ensuring safety and extended shelf-life.

How does it work?
The packaging temperature of a baked product and its cooling gradient are intimately related. There needs to be a proper balance between product temperature and moisture to ensure adequate slicing and packaging processes.

Once baked bread has cooled down to the optimum packaging temperature 95–105°F (35–40°C), its moisture content will drop which helps the finished product achieve optimum keeping qualities.

Application
Factors that affect packaging temperature include:

• Baking process (over- and under-baking)

• Bread cooling process (over- and under-cooling)

• Storage conditions of packaging material

• Temperature and relative humidity of the environment in the plant (temperature may be high in areas where the oven is close to the packaging area and in the absence of proper ventilation)

Quality considerations
Improper packaging temperatures can negatively impact the quality of the baked product. During bread cooling, a large temperature gradient can develop between the crust and the crumb. As cooling continues, this gradient will be reduced gradually and eventually reaches zero. Effects of improper packaging temperatures are detailed below.

Product temperature too low:

• Product has cooled and dried longer than normal

• The finished product is drier and firmer with brittle, harsh eating qualities (crumbly)

• The dryness and loss of moisture contribute to a faster loaf staling

• Significant moisture loss in bread crumb

Product temperature too high:

• Insufficient cooling and drying of product

• Bread sidewalls will be weak and may collapse while passing through the slicer

• Loaf slices will be ragged and may tear due to excessive moisture

• Bread crumb is too soft

• Gumming up of the slicer blades (increased downtime)

• Excess moisture due to condensation inside the wrapper

Product considerations
• Variety breads: Packaging temperature for variety bread such as rye breads should be lower, around 90ºF (32ºC). Such temperatures are recommended due to the product’s tendency to become gummy.

• Frozen dough operations: After blast-freezing, dough frozen pieces should be immediately packaged to maintain the product’s core temperature within the range of 10–0°F (-12 to -18°C).

Packaging temperature impact on product quality and shelf-life

Wrapping baked goods at very high temperatures (product insufficiently cooled) leads to moisture condensation within the wrapper. This greatly affects product’s shelf-life as condensation encourages localized increases in product water activity and subsequent mold growth.

Upon cooling of sliced and packaged bread, excessive moisture is lost to condense within the wrapper. This moisture will be reabsorbed by the product crust encouraging its further softening (critical for the texture of crispy products).

https://www.linkedin.com/pulse/bread-manufacturing-processes-hamed-ali-htbqf/


# خصائص التعامل مع العجين

من أهداف عملية الخلط في صناعة الخبز تحقيق توازن مثالي في خصائص التعامل مع العجين. هناك أربعة خصائص رئيسية للتعامل مع العجين:

1. التمددية (Extensibility):
قدرة العجين على التمدد والاتساع عند تطبيق قوى أو ضغط عليه. تعتبر التمددية مهمة لتشكيل العجين إلى أشكال مختلفة، كما أنها تسمح للعجين بالتمدد مع زيادة ضغط الغاز الناتج عن تخمر الخميرة.

2. المرونة (Elasticity):
قدرة العجين على العودة إلى شكله الأصلي بعد إزالة القوة المطبقة عليه. ببساطة، هي قدرة العجين على "الارتداد" عند تمديده.

3. مقاومة التشوه (Tenacity):
قدرة العجين على مقاومة التشوه عند تمديده. العجين الذي يتميز بمقاومة عالية للتشوه يصعب التعامل معه أثناء مراحل التشكيل، مثل عجين الفطائر المصفح الذي يصعب تمديده إذا كان شديد المقاومة.

4. اللزوجة (Stickiness):
قدرة العجين على الالتصاق بالأسطح التي يتلامس معها. يجب أن تكون اللزوجة في حدها الأدنى لضمان تشكيل العجين ونقله بسهولة. في معظم الحالات، تعتبر اللزوجة غير المرغوبة إحدى التحديات التشغيلية التي تواجه المخابز.

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# كيف تعمل خصائص العجين؟
من المهم فهم معنى خصائص العجين، وكيف تتأثر، وكيف تؤثر على المنتجات النهائية:

- التمددية: تتعلق بقدرة العجين على التمدد تحت الضغط. التمددية المناسبة ضرورية للسماح للعجين بالتشكل والاحتفاظ بالغازات الناتجة عن التخمير.
- المرونة: تتعلق بقدرة العجين على العودة إلى شكله الأصلي. العجين المرن للغاية قد يكون صعب التشكيل.
- مقاومة التشوه: العجين الذي يتمتع بمقاومة عالية للتشوه يصعب تشكيله، وقد يؤدي إلى نتائج غير مرضية في المنتجات النهائية.
- اللزوجة: تعتبر مشكلة في العمليات الإنتاجية، ويمكن تقليلها من خلال تعديل نسبة الماء.

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# العوامل المؤثرة على خصائص التعامل مع العجين
تشمل العوامل التي تؤثر على خصائص التعامل مع العجين ما يلي:

- نوع القمح المستخدم ونسبة استخلاصه.
- نسبة الماء المضاف (الترطيب).
- وجود مكونات مثل البروتينات المكونة للجلوتين، والنشا المتضرر.
- جودة البروتينات المكونة للجلوتين (الجليادين والجلوتينين).
- وجود جسيمات النخالة التي تعطل شبكة الجلوتين.
- وجود دقيق حبوب غير القمح.
- ظروف الخلط (مثل السرعة، ووقت الخلط).
- درجة تطوير الجلوتين.
- درجة حرارة العجين.
- وجود مكونات تتنافس مع الماء مثل السكريات والملح.
- إضافة مكونات وظيفية مثل المواد المؤكسدة والاختزالية.
- فترة راحة العجين.

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# خصائص العجين حسب حالته
- عجين مفرط التمدد (Extensible):
يتميز بـ:
- ارتخاء مفرط.
- تدفق زائد في القوالب.
- نتائج نهائية قد تشمل انهيار المنتج بسبب الزيادة المفرطة في الحجم.

- عجين شديد المرونة (Elastic):
يتميز بـ:
- صلابة زائدة.
- مقاومة كبيرة للماكينات أثناء التشكيل.
- نتائج نهائية تشمل نقص في الحجم وضعف المظهر العام للمنتج.

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# تصميم غرف التخمير (Proofer Design)

غرف التخمير هي معدات مصممة لتوفير ظروف محددة من درجة الحرارة والرطوبة النسبية لزيادة نشاط الخميرة في العجين المخمر. تشمل الشروط المثالية للتخمير:

- درجة الحرارة: 35–43 درجة مئوية.
- الرطوبة النسبية: 80–85%.
- الوقت: 40–70 دقيقة.

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# التعبئة الحرارية (Packaging Temperature)

درجة الحرارة المثلى للتعبئة هي درجة الحرارة التي يكون عندها المنتج المخبوز قد تم تبريده وتقطيعه وأصبح جاهزًا للتعبئة. درجة الحرارة المناسبة تضمن الاحتفاظ بالرطوبة المثلى لمنع التكثف وضمان سلامة المنتج وعمر تخزين أطول.

- درجة حرارة منخفضة جدًا أثناء التعبئة:
تؤدي إلى منتج أكثر جفافًا وصلابة مع انخفاض في العمر الافتراضي.

- درجة حرارة مرتفعة جدًا أثناء التعبئة:
تؤدي إلى تكثف الرطوبة داخل العبوة، مما يعزز نمو العفن وتأثير سلبي على الجودة.

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# الخلاصة:
فهم خصائص العجين وكيفية التحكم بها هو مفتاح إنتاج منتجات مخبوزة ذات جودة عالية. التوازن بين المرونة والتمددية، والحد من مقاومة التشوه واللزوجة، يمكن أن يحسن من كفاءة الإنتاج وجودة المنتج النهائي.
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