Proteins are essential macronutrients for the human diet. They are the primary source of nitrogen and are fundamental for body structure and functions. The plant protein quality (PPQ) refers to the bioavailability, digestibility, and amino acid composition. The digestibility specifies the protein quantity absorbed by an organism relative to the consumed amount and depends on the protein structure, previous processing, and the presence of compounds limiting the digestion. The latter are so-called antinutritional factors (ANF), exemplified by phytates, tannins, trypsin inhibitors, and lectins. Animal proteins are known to have better digestibility than plant proteins due to the presence of ANF in plants. Thus, the inactivation of ANF throughout food processing may increase the PPQ. New food processing, aiming to increase the digestibility of plant proteins, and new sources of proteins are being studied for the animal protein substitution. Here, it is presented the impact of processing on the protein digestibility and reduction of ANF. Several techniques, such as cooking, autoclaving, germination, microwave, irradiation, spray- and freeze-drying, fermentation, and extrusion enhanced the PPQ. The emerging non-thermal technologies impact on protein functionalities but require studies on the protein digestibility. How to accurately determine and how to improve the protein digestibility of a plant source remains a scientific and technological challenge that may be addressed by novel or combining existing processing techniques, as well as by exploring protein-enriched by-products of the food industry.

The tomato is a member of the Solanaceae family and is a crop that is widely cultivated around the world due to its sweet, sour, salty, juicy, and nutritious berries. The processing of tomatoes generates a significant amount of waste in the form of tomato pomace, which includes seeds and skin. Tomato seeds are reservoirs of various nutrients, such as proteins, carbohydrates, lipids, minerals, and vitamins. These components make tomato seeds an important ingredient for application in food matrices. This review discusses the functional food properties of tomato seeds and their scope of utilization as major ingredients in the functional food industry. In addition, this review describes the development of tomato seeds as a potential nutritional and nutraceutical ingredient, along with recent updates on research conducted worldwide. This is the first review that demonstrates the nutritional profile of tomato seeds along with its diverse functional food properties and application as a functional food ingredient.