Enzymatic browning of sprouts during storage is a serious problem negatively influencing their consumer quality. Identifying and understanding the mechanism of inhibition of polyphenol oxidases (PPOs) in lentil sprouts may offer inexpensive alternatives to prevent browning. This study focused on the biochemical characteristics of PPOs from stored lentil sprouts, providing data that may be directly implemented in improving the consumer quality of sprouts. The purification resulted in approximately 25-fold enrichment of two PPO isoenzymes (PPO I and PPO II). The optimum pH for total PPOs, as well as for PPO I and PPO II isoenzymes, was 4.5–5.5, 4.5–5.0, and 5.5, respectively. The optimal temperature for PPOs was 35 °C. Total PPOs and the PPO I and PPO II isoenzymes had the greatest affinity for catechol (K_m = 1.32, 1.76, and 0.94 mM, respectively). Ascorbic acid was the most effective in the inhibition of dark color formation by total PPOs, and showed ca. 62%, 43%, and 24% inhibition at 20-, 2-, and 0.2-mM concentrations. Ascorbic acid, l-cysteine, and sodium metabisulfite (20 mM) significantly inhibited color development in the reactions catalyzed by both isoenzymes of PPO. Ba²⁺, Fe³⁺, and Mn²⁺ (10 mM) completely inhibited PPO activity. This study of the effect of antibrowning compounds and cations on PPO activity provides data that can be used to protect lentil sprouts against enzymatic browning during storage and processing.

Probiotics improve consumers' health and additionally may positively influence the microbiological and organoleptic quality of food. In the study, legume sprouts were inoculated with Lactobacilllus plantarum 299V to produce a new functional product ensuring the growth and survival of the probiotic and high microbiological quality of the final product. Legume sprouts, which are an excellent source of nutrients, were proposed as alternative carriers for the probiotic. The key factors influencing the production of probiotic-rich sprouts include the temperature (25°C) of sprouting and methods of inoculation (soaking seeds in a suspension of probiotics). Compared to the control sprouts, the sprouts enriched with the probiotic were characterized by lower mesophilic bacterial counts. In the case of fresh and stored probiotic-rich sprouts, lactic acid bacteria (LAB) accounted for a majority of total microorganisms. The Lb. plantarum population was also stable during the cold storage. The high count of LAB observed in the digest confirmed the fact that the studied sprouts are effective carriers for probiotics and ensure their survival in the harmful conditions of the digestive tract in an in vitro model. Enrichment of legume sprouts with probiotics is a successful attempt and yields products for a new branch of functional foods.

In this study, the effect of the addition of freeze-dried raspberry pomace on the content of phenolic compounds and the antioxidant and anti-inflammatory activity of wafers was investigated. Particular attention was paid to the biological activity of the potentially bioavailable fraction of polyphenols extracted via gastro-intestinal digestion. In the basic recipe for the waffle dough, flour was replaced with freeze-dried raspberry pomace in the amount of 10%, 20%, 30%, 50%, and 75%. The content of total phenolic compounds, phenolic acids, flavonoids, and anthocyanins in ethanol and buffer extracts and after in vitro digestion increased with the increase in the addition of pomace. A similar relationship was noted for antioxidant properties: ability to neutralize ABTS—2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) and DPPH—1,1-diphenyl-2-picrylhydrazyl radicals, iron II chelating ability, and reduction power. The extracts obtained after the simulated digestion showed the highest activities, which confirms that the polyphenols are a potentially bioavailable fraction. Extracts from the fortified wafers effectively inhibited the activity of enzymes involved in the generation of free radicals and induction of inflammation, i.e., xanthine oxidase (XO), lipoxygenase (LOX), and cyclooxygenase 2 (COX-2). The lowest IC50 values were determined for extracts after in vitro digestion. The sensory evaluation of the prepared wafers showed that the wafers fortified with 20% pomace achieved optimal scores. Enrichment of confectionery products with waste products from the fruit and vegetable industry can be a good way to increase the proportion of biologically active polyphenols in the diet and brings benefits to the environment.