CHAPTER XI
Bread and Bread Making
502. Define leavened and unleavened bread. 503. Why is yeast used in bread making? 504. Give the characteristics of a good loaf of bread. 505. Why is flour used for bread making purposes? 506. Name the eight chemical changes that take place during bread making. 507. To what extent do losses in dry matter occur during bread making? 508. What compounds suffer losses during bread making? 509. What is yeast? 510. What chemical changes does it produce? 511. What becomes of these products during bread making? 512. How is compressed yeast made? 513. What part does the alcohol take in bread making? 514. What temperature is reached in the interior of the loaf during bread making? 515. Through what chemical changes does starch pass during bread making? 516. To what extent are soluble carbohydrates formed? 517. In what way is starch acted upon mechanically? 518. Explain the structure of the starch grains in flour and in dough after they have been acted upon by the yeast ferments. 519. To what extent are acids produced in bread making? 520. What becomes of the acids formed? 521. How may the acids thus developed affect the properties of other chemical compounds? 522. To what extent are volatile carbon compounds, other than carbon dioxid and alcohol, liberated during bread making? 523. What changes occur to the various proteids during the process of bread making? 524. Why do flours vary in quality of gluten? 525. To what extent do losses of nitrogen occur during bread making? 526. How much of the total nitrogen of flour is present as proteids? 527. How is the fat of flour affected during the process of bread making? 528. What effect does the addition of 10 per cent of wheat starch to flour have upon the size of the loaf? 529. What effect does the addition of 10 per cent of wheat gluten to flour have upon the size of the loaf? 530. What relationship exists between gluten content and capacity of a flour to absorb water? 531. Give the general composition of bread. 532. What factors influence its composition? 533. What effect does the use of skim milk and lard in bread making have upon composition? 534. How does the temperature of the flour influence the bread-making process? 535. Why is it necessary to vary the process of bread making in order to get the best results with different kinds of flour? 536. To what extent are the nutrients of bread digested? 537. How does graham bread compare in digestibility with white bread? 538. How do graham and entire wheat breads compare in nutritive value with white bread? 539. What value do graham and entire wheat breads have in the dietary? 540. Why is white bread generally preferable in the dietary of the laboring man? 541. How do graham and entire wheat flours compare in chemical composition with white flour? 542. How do they compare in mechanical composition? 543. To what is the difference in digestibility supposed to be due? 544. Are graham and entire wheat breads necessary in a ration as a source of mineral elements? 545. What is the main difference in composition between old and new bread? 546. How do different kinds of bread made from the same flour compare in composition and nutritive value? 447. How does toast differ in composition from bread? 548. What influence does toasting have upon digestibility? 549. What is gained by toasting bread? 550. How does bread compare in nutritive value with other cereal foods? 551. How does bread compare in nutritive value with animal foods?