Bitterness is a widespread sensory defect during cheese ripening caused by the accumulation of low molecular weight peptides ($\lt 6000\text{ Da}$) rich in hydrophobic amino acid residues (such as leucine, proline, phenylalanine, and valine), primarily derived from the enzymatic cleavage of $\beta$-casein and $\alpha_{s1}$-casein by coagulant and starter proteases. If starter peptidases fail to degrade these hydrophobic peptides into free amino acids, bitterness develops.

Option analysis:

• Hydrophobic peptides: Correct. Bitterness is directly elicited by hydrophobic peptides stimulating bitter taste receptors on the tongue.
• Hydrophilic peptides: Incorrect. Do not elicit a bitter taste.
• Amino acids: Incorrect. Free amino acids contribute savoury/brothy and umami taste, not cheese bitterness.
• Sulphur compounds: Incorrect. Provide pungent, garlicky or cheddar-like sulfur notes.

Ripening mechanisms in surface mold-ripened soft cheeses (Camembert and Brie):

• Statement (I) is correct: Ripening proceeds centripetally (from the outer mold-covered surface towards the internal core), characterized by gradual softening and liquefaction of the curd matrix from the rind inward.
• Statement (II) is correct: Surface growth of Penicillium camemberti metabolizes lactic acid into carbon dioxide and water, raising surface pH from $4.6$ up to $7.0\text{ to }7.5$. Mold proteases diffuse inward causing extensive proteolysis, while the alkaline surface creates a chemical gradient that causes soluble calcium phosphate to migrate from the interior to the rind, solubilizing the sub-surface casein network and softening texture.
  
  Option analysis:
• Both Statement (I) and Statement (II) are correct: Correct.
• Both Statement (I) and Statement (II) are incorrect: Incorrect.
• Statement (I) is correct but Statement (II) is incorrect: Incorrect.
• Statement (I) is incorrect but Statement (II) is correct: Incorrect.